bluuebunny/crossref_metadata_2025_split huggingface dataset:
The somatotopic organization of the cat trigeminal ganglion as determined by the horseradish peroxidase technique
Authors: Marfurt Carl F. 
Published: February 2005

AbstractThe somatotopic organization of the cat trigeminal ganglion has been investigated in the present study by using the horseradish peroxidase (HRP) technique. In separate animals, the corneal, supraorbital, infraorbital, inferior alveolar, or mental branches of the trigeminal nerve have been transected and then soaked in concentrated solutions of HRP. Retrogradely labeled corneal and supraorbital neurons have been found, with extensive overlap between the two cell populations, in the anteromedial region of the trigeminal ganglion. Inferior alveolar and mental neurons have been found to possess similar distributions within the posterolateral part of the trigeminal ganglion. Infraorbital cells have been localized in a central position. The cell bodies of any given nerve are found in at least minimal numbers in all dorsoventral levels of the trigeminal ganglion. However, cell bodies of origin of the supraorbital nerve and the lateral branch of the infraorbital nerve, innervating more posterior or lateral areas of the head and face, are found in greater numbers dorsally. Conversely, cell bodies of origin of the medial branch of the infraorbital nerve, the inferior alveolar nerve, and the mental nerve, supplying more rostral or intraoral areas of the orofacial region, are present in greater numbers ventrally. In contrast, corneal neurons are distributed uniformly in the dorsoventral axis. The ophthalmic and maxillary regions of the trigeminal ganglion appear to be well segregated, whereas the maxillary and mandibular regions exhibit a somewhat greater degree of overlap. Cell bodies of corneal afferent neurons range from 20 to 50 μm in diameter, whereas those of supraorbital, infraorbital, inferior alveolar and mental neurons measure from 20 to 85 μm. It is concluded from the findings of the present work that much of the cat trigeminal ganglion is organized somatotopically in not only the mediolateral axis but also in the dorsoventral axis.
An improved method for processing single cells for electron microscopy utilizing agarose
Authors: Yuan Lydia C. , Gulyas Bela J. 
Published: February 2005

AbstractAn improved method is presented for processing single cells for electron microscopy. Agarose, which has a low (30°C) gelling temperature, was used as an initial embedding medium for single cells (spermatozoa and oocytes) and dissociated cell preparations (luteal cells and spleen cells). Dispersed cells of corpus luteum, spleen, and epididymal spermatozoa were placed in 1.5% agarose after aldehyde fixation. These fixed cells, embedded in agarose, were packed into a dense pellet by centrifugation, postfixed, then embedded in Epon. Mammalian eggs were not centrifuged; instead, they were embedded in agarose discs. Cells embedded in agarose were cooled below 30°C to allow for gelling, then processed for electron microscopy. Because agarose has a low gelling temperature, some heat‐labile substances were preserved, as demonstrated by retention of peroxidase activity using the DAB histochemical method. The agarose embedding procedure is both rapid and facile, and has proven to be of value in the handling of fragile single cells for electron microscopic studies.
Filamentary rod‐shaped granules in clara cells of rats
Authors: Baert J. , Vandenberghe M. P. 
Published: February 2005

AbstractThe bronchiolar Clara cells of rats contain characteristic rodshaped granules always surrounded by a unit membrane. These granules contain thin filaments about 9 to 10 nm in diameter lying in a pale matrix. Our morphological results suggest that the filamentary rod‐shaped granules originate from the common, round‐to‐oval, electron‐dense Clara cell granules, as we found different intermediate structures between these two kinds of granules. The electron‐dense granules are digested by pepsin, whereas the filamentary rod‐shaped granules are apparently not affected. The biochemical nature and the possible function of the filamentary rod‐shaped granules are also discussed in relation to the secretory activity of the Clara cells.
Interfollicular smooth muscle in the skin of the domesticated pig (Sus scrofa)
Authors: Stromberg M. W. , Hwang Y. C. , Monteiro‐Riviere N. A. 
Published: February 2005

AbstractAn interfollicular smooth muscle that spans the triad of hair follicles has been identified in the skin of the domesticated pig (Sus scrofa). This muscle has been previously noted by other investigators and identified as an arrector pili muscle. However, it cannot be interpreted as such for the following reasons: (1) It lies opposite the arrector pili muscle on the follicle; (2) the orientation of its fibers is perpendicular to those of the arrector pili; (3) the two muscles are not continuous; their attachments are different; and (4) contraction of the interfollicular muscle would have little effect on erection of the hairs. Based on structural evidence, it is postulated that upon contraction the muscle draws the base of the three aligned follicles together into a triangular conformation. In so doing, it may rotate the outer two follicles of the triad. Its specific functional role is unknown.
Regeneration of submandibular salivary gland autografted in the rat tongue
Authors: Sharawy Mohamed , O'Dell Norris L. 
Published: February 2005

AbstractAutologous SMG fragments were implanted in tongues of male rats which were sacrificed 15–20 min, 24 hr, 72 hr, 1 week, or 8 weeks after implantation. The tongues were excised, fixed, and processed for light and electron microscopy. In addition, some rats were injected with [3H]‐thymidine 1 hr before sacrifice and the labeling indices (L.I.) of the salivary epithelial and interstitial cells were calculated. Twenty‐four hours after implantation, SMG autografts showed massive central necrosis with some acini and ducts surviving at the periphery of the lobules. There was marked infiltration of the autografts with neutrophils and macrophages. Also the basal laminae surrounding the necrotic acini and ducts remained intact. The morphology of the autografts after 72 hr was similar to that after 24 hr except that there was additional necrosis and acini and ducts could no longer be identified in the autografts. By 1 week after implantation, the autografts showed lobular morphogenesis, ductal branching, and revascularization. At this time, the regenerating salivary epithelium appeared undifferentiated with no evidence of secretory granules. The L.I. of interstitial and ductlike structures showed significant increases over control values at 1 week after implantation, and then declined toward control levels by 3 weeks after implantation. By 8 weeks after implantation, there was evidence of acinar and striated ductal cytodifferentiation in two autografts. The results emphasize the potential of SMG autografts to regenerate subsequent to severe tissue necrosis.
Ultrastructural changes in hamster lung four hours to twenty‐four days after exposure to elastase
Authors: Morris Shirley M. , Stone Philip J. , Snider Gordon L. , Albright John T. , Franzblau Carl 
Published: February 2005

AbstractA single endotracheal instillation of elastase initiates a series of changes in animal lungs that results in a condition resembling human panlobular emphysema. An ultrastructural examination of this series of changes was conducted on the lungs of male golden hamsters exposed to 3H‐methylated pancreatic elastase and sacrificed at intervals between 4 hour and 24 days after exposure to enzyme.Lung tissue between 4 and 48 hours showed evidence of hemorrhage and progressive degradation of elastic fibers. Very little indication of epithelial cell damage accompanied these changes. Four days after exposure to elastase, synthesis of new elastic fibers began with the appearance of small clumps of microfibrils in close association with interstitial cells, fibroblasts, and smooth muscle cells. There was also evidence of alterations in alveolar type II cells at this time. Small fibrillar elastic fibers continued to be present in the lung through twenty‐four days and may represent a slow repair process or may indicate a structural difference in elastic fibers synthesized after exposure to elastase. Evidence of the continued degradation of elastic fibers could be found up to 16 days after exposure to elastase, revealing that repair processes were occurring in some areas of the lung while destructive processes still predominated in other areas.
Morphological correlates of hormone secretion in the rat adrenal cortex and the role of filopodia
Authors: Pudney J. , Sweet P. R. , Vinson G. P. , Whitehouse B. J. 
Published: February 2005

AbstractRat adrenals in different states of stimulation were examined by transmission electron microscopy following perfusion fixation using an in situ isolated‐circulation technique. In unstimulated glands, intracortical capillaries were constricted and the cells of the cortex were pressed closely together with little development of filopodia or intercellular spaces. Glands fixed during the period of operative stress, or following a 1 hr perfusion with Adrenocorticotropic hormone (ACTH) showed that the radially orientated capillaries of the cortex were massively expanded, and the cells of both the glomerulosa and fasciculata exhibited an extensive development of filopodia on their surfaces. These filopodia extended into enlarged intercellular spaces, where they often entered into complex relationships with filopodia from neighboring cells.The development of filopodia by cells of the adrenal cortex was also observed using scanning electron microscope techniques. In cells either icubated with ACTH in vitro or isolated from adrenals of rats treated with ACTH in vivo, the filopodia were numerous, often branched, and could reach as much as 1 μm in length. In contrast, adrenal cells obtained from animals pretreated with cortisol were smooth surfaced.Other cell characteristics, including mitochondria, smooth endoplasmic reticulum, dense granules, and coated vesicles did not show such dramatic correlations with the state of stimulation. It is considered that the development of filopodia and intercellular space is related to secretory mechanisms in the rat adrenal cortex.
An electron microscopic radioautographic study of collagen secretion in periodontal ligament fibroblasts of the mouse: II. Colchicine‐treated fibroblasts
Authors: Cho Moon‐Il , Garant Philias R. 
Published: February 2005

AbstractColchicine administered intravenously depolymerized microtubules and disrupted the normal organization of the Golgi apparatus in periodontal ligament fibroblasts. Radioautography with 3H‐proline indicated that collagen secretion was completely inhibited during a period of approximately 4 hours following the onset of the colchicine effect. During this period of secretory inhibition, labeled collagen precursors were present within a variety of dense bodies, primarily located in a juxtanuclear location replacing the normal Golgi complex. The time course of 3H‐proline labeling from 2 to 8 hours suggested that small, newly formed dense bodies fused to form larger dense bodies and pleomorphic structures (zebra bodies), within which collagen precursors appeared to undergo partial polymerization. Autophagosomes, many labeled with 3H‐proline, also increased in number after colchicine administration. A gradual decline in 3H‐proline label occurred from 4 to 24 hours, presumably due to exocytosis of dense bodies or by the digestion of labeled collagen precursors within autophagosomes.These results support the concept that an intact microtubular network is essential for the organized transport of collagen precursors, from the rough endoplasmic reticulum to the Golgi apparatus, and the eventual transport and exocytosis of collagen secretory granules.
Utrastructural observations on melanosome aggregation in genetically defective melanocytes of the mouse
Authors: Koyama Yoh‐Ichi , Takeuchi Takuji 
Published: February 2005

AbstractCultivated mouse melanocytes with the genotype of D/‐ and d/d obtained from dorsal skin of infants, and the variant melanoma cells (subline agm) in which melanosomes were aggregated around the nucleus were characterized by means of electron microscopy. In D/‐ melanocytes, dendrites contained a number of microtubules and 10‐nm filaments, mitochondria, endoplasmic reticulum, and peripherally distributed melanosomes. On the other hand, in d/d melanocytes and agm cells, melanosomes were aggregated in the perinuclear region of the cell body. Their fibrous dendrites contained numerous microtubules and 10‐nm filaments, mitochondria, and endoplasmic reticulm. It is suggested that the interactive process of melanosomes with cytoskeletal elements is defective in d/d melanocytes, and that a similar defect is present in agm cells.
A morphologic and morphometric analysis of fetal lung development in the sheep
Authors: Alcorn Daine G. , Adamson T. Michael , Maloney John E. , Robinson Peter M. 
Published: February 2005

AbstractIn the sheep, fetal lung development proceeds to a later stage of maturity than in smaller laboratory animals. Of the four stages in pulmonary development recognizable in this species–embryologic, pseudoglandular, canalicular, and aveolar–the latter three are described in the present study using histologic, morphometric, and ultrastructural techniques. During the pseudoglandular stage, the major airways developed centrifugally. Cartilaginous, glandular, muscular, vascular, and neural elements were present in major airway walls from an early age. During the canalicular stage, volume expansion of the lung was accomplished by rapid growth of large terminal spaces. In the final stage, alveoli were formed following subdivision of the large terminal spaces by alveolar crests. The alveolar lining epithelium differentiated during the latter two stages producing a large increase in alveolar surface area, particularly during the alveolar stage; a large increase in pulmonary capillary surface area also accompanied alveolar development. Thus, just prior to birth, the fetal sheep lung has a well‐developed airway system and alveolar network, in preparation for postnatal gas exchange.
Ultrastructural stereologic analysis of fetal rabbit type II alveolar epithelial cells following maternal pilocarpine treatment or fasting
Authors: Smith Dennis M. , Shelley Sue A. , Balis John U. 
Published: February 2005

AbstractWe have previously reported that subcutaneous administration of 5 mg/kg pilocarpine HC1, a muscarinic agonist, to pregnant white rabbits on days 24 through 27 of gestation results in an acceleration of fetal lung maturation. In the present study the ultrastructural differences observed within alveolar type II cells of 28‐day fetuses from the pilocarpine and control groups were quantified by stereologic analysis. In addition, maturational changes occurring within the lungs of 28‐day fetuses obtained from pregnant rabbits which were fasted for 7 days (days 21–28) were similarly analyzed.Stereologic analysis revealed that the fetal type II cells in the pilocarpinetreated group possessed a significantly greater volume density of lamellar inclusion bodies and rough endoplasmic reticulum and a significantly smaller volume density of glycogen than did controls. The volume density values for fetal type II cells of the fasted group were, with the exception of the Golgi apparatus, found to be intermediate between those of the control and the pilocarpine‐treated groups. It was also noted that a high percentage of the lamellar inclusion bodies within type II cells of the fasted group appeared morphologically abnormal, being characterized by a highly irregular outline and tightly packed lipid membranes.The results of this study substantiate and quantify our previously reported observation of accelerated maturation in pilocarpine‐treated fetuses. In addition, they suggest a similar, though not as pronounced, effect of maternal fasting prior to delivery. However, the abnormal morphology of the lamellar inclusion bodies in the fasted group may reflect a qualitative change in the pulmonary surfactant produced by these fetuses.
Skull preparation using the enzyme‐active detergent technique
Authors: Mooney Mark P. , Kraus Eric M. , Bardach Janusz , Snodgass John I. 
Published: February 2005

AbstractWith the increasing use and need for macerated skulls and bony structures in medical research and resident and medical student studies, an economical, easy, and efficient method of obtaining cleaned and bleached specimens has been developed. The process requires short‐term skeletal simmering in a 10% solution of commercially available enzymatic detergent and water. Over 50 skulls have been macerated in our laboratory resulting in substantial saving in research money, time, and effort.
Isolation of human erythrocyte inside‐out vesicles alters their molecular architecture
Authors: Wise Gary E. 
Published: February 2005

AbstractInside‐out (I.O.) vesicles isolated from human erythrocyte ghosts induced to endocytose have been used for biochemical studies to determine localization of molecules within the membrane. It was the purpose of this study to examine such vesicles by freeze‐etch electron microscopy to determine the architecture of the peripheral proteins on the protoplasmic surface. Examination of the I.O. vesicles while still in the interior of the ghosts showed that a globular material was randomly distributed on the outer surface (protoplasmic surface of the original plasma membrane) of the I.O. vesicles. The random distribution of the globular material becomes altered, however, if the I.O. vesicles are isolated from the ghosts by shearing and centrifugation. Freeze‐etching of these isolated I.O. vesicles revealed that the globular material was now clustered on the protoplasmic surface (PS), as were the intramembranous particles (IMPs) in the extracellular face. Thus, the lateral mobility of the IMPs is dependent upon the distribution of molecules at the protoplasmic surface of the membrane. Moreover, this change in distribution of the globular material at the surface is not due to a partial loss of major membrane proteins, because SDS‐polyacrylamide gel electrophoresis revealed that equal amounts of the major proteins were present in nonisolated vesicles as compared to isolated vesicles. Although isolated I.O. vesicles have been used extensively to demonstrate that glycoproteins span the membrane, these results suggest that one should cautiously interpret data obtained from such isolated vesicles in view of the fact that there is an alteration of the distribution and perhaps configuration of molecules at the PS following isolation of I.O. vesicles.
Light and electron microscopic immunohistochemical localization of somatostatin in the endocrine and exocrine portions of the pancreas of the chick embryo (gallus domesticus)
Authors: Kalliecharan Rajdeo , Steeves John 
Published: February 2005

AbstractA discrete population of cells containing immunoreactive somatostatin was shown by the peroxidase antibody bridge technique at both the light and electron microscopic level to be present in the pancreas of chick embryos. Based on the stage of development, somatostatin‐positive cells, at the light microscopic level, were found in the alpha and beta islets, in isolated islets that did not correspond with any known alpha or beta islets, as well as in the acinar tissue. Quantitative determination indicated that, at all ages examined, there were a greater number of somotostatin cells associated with the alpha islets per square millimeter of tissue than with either the beta islets or acinar tissue of the exocrine pancreas.Ultrastructural observations on day 15 of development confirm and reinforce the light microscopic observations pertaining to the localization of the somatostatin‐positive cells. The results also show that the PAP reaction was localized only on the granules of the somatostatin positive cells. These granules were primarily found in the apical region of these cells adjacent to blood vessels.
A study of motor nerve terminals on cat nuclear bag1 intrafusal muscle fibers using the ChE staining technique
Authors: Kucera Jan 
Published: February 2005

AbstractMuscle spindles were traced in serial transverse sections of cat tenuissimus muscles. Histochemical staining for “myofibrillar” adenosine 5′‐triphosphatase was employed to identify nuclear bag1 intrafusal muscle fibers. Staining for cholinesterases (ChE) was used to demonstrate the termination sites of motor axons along the fibers. Several types of ChE deposits could be distinguished along the bag1 fibers based on intensity of staining and morphological characteristics. Most ChE deposits could be classified as either the “pale” or the “nonpale” plates. Some ChE active areas fitted neither of these two categories. Among 328 ChE “plates” encountered on 192 bag1 fiber poles, 197 (60%) were of the “pale” and 27(8%) of the “nonpale” type with 104(32%) remaining unclassified.These histochemical observations are discussed with regard to the current structural and functional concepts of motor innervation of the nuclear bag1 fiber. It is suggested that the histochemical (ChE staining intensity) and morphological (length and form) characteristics of bag1 fiber motor endings are not determined solely by the nature of the corresponding motor axons.
Cell surface specializations and intercellular junctions in human amniotic epithelium: An electron microscopic and freeze‐fracture study
Authors: King Barry F. 
Published: February 2005

AbstractCell surface specializations and intercellular junctions of human term amniotic epithelium were examined by conventional thin‐section electron microscopy, after staining with the cationic probes ruthenium red and cationic ferritin, and by freeze‐fracture methods. Desmosomes were the predominant type of intercellular junction and often the most apical of the junctional types. In freeze‐fracture replicas, desmosomes were characterized by roughly circular areas of large, often irregular, P‐face intramembranous particles. Gap junctions were identified in the laterobasal regions between cells. In thin sections they were characterized by a narrow intercellular space, and in freeze‐fracture replicas had a typical plaquelike arrangement of P‐face intramembranous particles and E‐face depressions. Hemidesmosomes at the basal cell surface were characterized by occasional large particles and clusters of particles on both the E and P fracture faces. No evidence of tight junctions was found. The apical cell surface was heavily stained by both ruthenium red and cationic ferritin, indicating the negatively charged nature of this surface. Ruthenium red penetrated between the epithelial cells and bound to anionic materials on the lateral cell surfaces, especially at the location of desmosomes. Below the base of the intercellular cleft, large ruthenium red‐positive granules were present in the extracellular matrix. The possibility that the anionic substances in the intercellular region may contribute to the control of permeability in the amniotic epithelium is discussed.