bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitoses in peripheral pulmonary epithelium: The effect of colchicine
Authors: Baron David A. , Esterly John R. 
Published: February 2005

AbstractInjury in the periphery of the lung was studied in rats given intratracheal trypsin. Mitotic figures were noted in the alveolar epithelium, and colchicine enhanced the yield. Of 65 mitotic figures examined in detail, 46 were present in the alveolar epithelium. Epithelial mitoses were confined to type II cells, many of which contained lamellar inclusions, abundant rough endoplasmic reticulum, and luminal microvilli. Mitoses were not seen in type I cells or in less well differentiated epithelial cells, but they were noted in occasional endothelial and interstitial cells. Colchicine‐arrested type II cells were distinguished by radially disposed chromosomes surrounding pairs of centrioles and randomly oriented microtubules. In addition, many of these cells showed a pronounced cortical zone, devoid of microvilli, and others showed cytotoxic degenerative changes. These observations indicate that the alveolar epithelium is renewed exclusively by division of differentiated type II cells.
“Silver dust”—a tool to study growth interrelationships between bone, periosteum and muscle
Authors: Grimm Arthur F. , Katele Kazimieras V. 
Published: February 2005

AbstractA cylinder of gelatin containing silver spongy granules was placed in and lay within the masseter muscle, the periosteum, and the mandible, and terminated in the medial pterygoid muscle of young (3 month‐old) growing miniature pigs.On the basis of an animal sacrificed one week after placement of the cylinder, it was found that the suspending gelatin was removed by cellular activity. Nine months later the remaining animals were sacrificed. Periodic X‐rays were taken during the course of the experiment. After sacrifice, the mandible and associated tissues were histologically examined. The results of this study suggest that the silver granules in the muscles maintained their location during growth; the silver granules in the mandible moved forward with mandibular growth. “Slippage” appeared to occur external to the fibrous layer of the periosteum; the site of movement was revealed by the trail of the silver granules. The described method should prove of value in studying the growth interrelationships between bone, periosteum, and muscle.
Specific granules of the rat atrial muscle cell
Authors: Seiden David 
Published: February 2005

AbstractThe specific granules found in the atrial cardiac muscle cells of the normal rat were studied. The ultrastructural appearance of these granules demonstrates a fixative‐dependent lability. Fixation with cacodylate buffered aldehydes yields three types of granules. However, fixation with phosphate buffered aldehvdes or primary fixation with OsO4 yields granules of uniform appearance. The granules are found predominantly in the perinuclear zone; 78% of the granules are within ten linear micrometers of the center of the nucleus. Two independent methods of measurement demonstrate spherical diameters of these granules of 0.30 μm and 0.37 μ respectively. The granules are found in greater concentration at one pole of the nucleus than at the other. On the high density side there are 4.07 granules/μm3 which occupy 5.8% of the cytoplasmic volume. On the low density side there are 2.15 granules/μm3 which occupy 3.0% of the cytoplasmic volume. The granules at both poles are the same size. Atrial walls were incubated in a modified Tyrode's solution. One hour of incubation caused no change in the atrial granules. Addition of norepinephrine or L‐Dopa resulted in the appearance of more granules but the size of the granules remained the same. Incubation with reserpine had no effect upon the atrial granules. Apparently the atrial myocardial cell is stimulated by exogenous catechol‐amine to synthesize more atrial granules which themselves do not appear to contain catecholamines.
Crystalloids of actin‐like filaments in the sertoli cell of the swine testis
Authors: Toyama Yoshiro , Obinata Takashi , Holtzer Howard 
Published: February 2005

AbstractNormal swine testes, congenital cryptorchid swine testes, and normal human testes were exposed to HMM (heavy meromyosin) after either glycerination or saponin treatment in order to determine whether the fine filaments composing the crystalloids in the Sertoli cells are actin‐like. The microfilaments of the crystalloids in the Sertoli cells of the cryptorchid swine testes bind HMM to form arrowhead complexes. Short bundles of microfilaments observed in the basal part of the Sertoli cells in both normal and cryptorchid testes also bind HMM. Similar bundles of HMM‐bound filaments are observed in the vicinity of spermatocytes. The periodicity of the arrowhead complexes is about 35 nm, and all arrowheads on a given filament point in the same direction. In addition, the polarity of the HMM‐bound filaments in a given crystalloid or bundle is uni‐directional. A mechanism for the formation of the swine crystalloids has been suggested by Toyama (′75), and the results of this study strongly support this hypothesis.Fine filaments of Charcot‐Boettcher's crystalloid in human Sertoli cells did not bind HMM. Therefore the fine filaments of the human crystalloid are not actin‐like in nature.
Cell junctions in the endothelia and connective tissue of the rat choroid plexus
Authors: van Deurs B. 
Published: February 2005

AbstractCell junctions between endothelial cells and between connective tissue cells (leptomeninges) of the rat choroid plexus were studied by freeze‐fracture. Special attention was paid to the problems of identifying fractured cell membranes and fracture faces. Tight junctions in arterioles are comprised of continuous small‐meshed networks of strands appearing as shallow grooves with aligned particles on E‐faces, and low ridges with some particles on P‐faces. In the fenestrated capillaries the tight junctions are represented by discontinuous, isolated slightly elevated ridges with some particles on P‐faces, and corresponding shallow grooves devoid of particles on E‐faces. Junctions in venules appeared as a less developed version of the junctions in the fenestrated capillaries. Extended areas of the meningeal cell membranes exhibit cell junctions. Tight junctions in this tissue are comprised of a loose discontinuous arrangement of isolated, often branched junctional elements. On P‐faces the elements appear as elongated crests with a distinct furrow running along the edge of the crest, occupied by a few particles. On E‐faces corresponding elongated impressions are present and occupied by aligned particles and a few short bars. The arrangement of these tight junction elements are not supportive of any significant barrier function. Small gap junctions occur “freely” in the membrane, or they are sometimes surrounded by tight junction elements. Very large gap junctions (up to about 10,000 particles) are mostly surrounded and interconnected by tight junctional elements. The possible significance of the variability of gap junction size, and the relation to tight junction elements is discussed.
Focal laminate segments in cytoplasmic processes of mouse myocardial fibroblasts
Authors: Forbes M. S. , Sperelakis N. 
Published: February 2005

AbstractIn mouse ventricular myocardium, we have found unusual fibroblasts whose cellular processes in some regions are particularly flattened and which contain linearly‐arranged, electron‐opaque structures (“central laminae”). The morphology of these focal laminate segments of fibroblast processes suggests that the intracellular laminae are adhesive entitieswhich hold the plasmalemmata above and below them in close parallel apposition for short distances.
Morphology of the atrioventricular node, bundle and proximal bundle branches: A study employing computerized reconstruction
Authors: Roberts Nigel K. , Castleman Kenneth R. 
Published: February 2005

AbstractThe morphology of the human atrioventricular node, atrioventricular bundle and bundle branches is described. A block of tissue bounded by the ostium of the coronary sinus, the pars membranacea, the septal leaflet of the tricuspid valve and the atrial and ventricular septa is removed. This block is then sectioned serially from the right endocardial surface in the frontal plane of the heart. Sectioning in this way produces fewer sections than from techniques previously described. Outlines of the atrioventricular node, atrioventricular bundle and proximal bundle branches are digitally registered and stored in a computer. Three dimensional reconstructions of the structures are then generated by computer and displayed on an oscilloscope so that the entire three dimensional image can be rotated in any plane. Stereoscopic image pairs are produced to assist perception of the shape of the atrioventricular node, bundle and branching patterns of the bundles. This technique is unique in that it describes a method from which a relatively small number of histologic sectionsare generated permitting not only a complete histologic examination, but also a study of the morphology of the area.
Morphogenesis of rod cells in the retina of the albino rat: A scanning electronmicroscopic study
Authors: Galbavy Edward S. J. , Olson Mark D. 
Published: February 2005

AbstractThis study presents scanning electron microscopic (SEM) observations of topographicalchanges that occur during morphogenesis of rod cells in the albino rat. Correlative transmission electron microscopy (TEM) was also utilized. Albino rats ranging in age from birth to three weeks were used for the study. Tissues were prepared by conventional methods for SEM and TEM.At birth, numerous irregularly arranged inner segments extend from the external surface of the sensory retina. They are spherical, smooth surfaced and possess a randomly oriented cilium. The internal morphology of these immature inner segments is comparable to that observed in other vertebrate species. Statistical analysis reveals a rapid increase in the number of rod cells during the first week. This period is characterized by the elongation of inner segments and their associated cilia. Microvilli project from the apices of Müller cells, but not from adjacent inner segments.By day 5, cilia occasionally display small bulbous outer segments. They are more numerous by day 8 and are usually eccentrically positioned at the tips of cilia. By day 11, outer segments are abundant and frequently obscure from view the underlying inner segments and associated cilia. Elongated cylindrical outer segments are present within the posterior retina at the end of the second week. However, rod cell morphogenesis lags in the peripheral retina. Topographical variations between developing photoreceptor cells in mammalian and non‐mammalian retinas are discussed.
The origin of the extrinsic adrenergic innervation to the rat ovary
Authors: Lawrence Irvin E. , Burden Hubert W. 
Published: February 2005

AbstractCutting the suspensory ligament reduced the ovarian content of norepinephrine (NE) to less than half that of controls and only a few blood vessels had perivascular fibers and an occasional nerve remained in the interstitial gland. Cutting the ovarian plexus had a less drastic, but similar effect on the ovarian content of NE and on the pattern of ovarian adrenergic nerves. Cutting both the suspensory ligament and ovarian plexus eliminated visualization of ovarian adrenergic nerves, but some ovarian NE was still measurable. Fluorescence and electron microscopic studies of the suspensory liagament revealed a large adrenergic nerve embedded in smooth muscle of the ligament. The nerve was also acetylcholinesterase‐positive. Cutting the celiac plexus or incising a small nerve lateral to the plexus and medial to the origin of the suspensory ligament, had the same effect on the ovarian adrenergic nerves as cutting the suspensory ligament. It is concluded that the extrinsic adrenergic nerves to the rat ovary reach the organ by two routes: one via the nerve in the suspensory ligament (superior ovarian nerve), and one via the traditionally described ovarian plexus along the ovarian artery.
Morphologic abnormalities in the postnatal differentiation of CA1 pyramidal cells and granule cells in the hippocampal formation of the Ataxic mouse
Authors: Burt Alvin M. 
Published: February 2005

AbstractThe postnatal differentiation of the hippocampal formation of the ataxic mouse was studied. Brains from ataxic mice (axJ/axJ) and littermate controls (+/?), from 19 to 51 days of age, were either impregnated according to a Golgi‐Cox procedure or sectioned and stained with Weil‐hematoxylin and Darrow Red. The hippocampus and dentate gyrus, although somewhat reduced in cross‐sectional area in the ataxic brain, appeared to have a normal complement of both pyramidal cells and granule cells, respectively. Examination of Golgi‐Cox material showed significant differences in the differentiation of the dendritic tree of both pyramidal and granule cells. At 41 days the height of the apical dendrite of CA1 pyramidal cells in the ataxic brain was 76% of the control value, and the width was only 35%. Similarly, the basal dendritic tree was narrower in the ataxic mouse. In the dentate gyrus of the 41‐day ataxic brain, the height of the granule cell dendritic tree was only 74% of the control value. These and other alterations in the dendritic morphology of both CA1 pyramidal cells and granule cells can be explained by a lack of growth of the dendritic tree during the developmental period studied. These findings are discussed in relation to other studies on intrinsic and extrinsic factors and their effect on normal hippocampal differentiation.
Heterogeneity of the MtTW15 mammosomatotropic tumor. II. Characterization of parenchymal cells by superimposition immunocytochemistry and electron microscopy
Authors: Parsons J. A. , Baskin D. G. , Erlandsen S. L. 
Published: February 2005

AbstractLarge MtTW15 tumors, which secrete growth hormone (GH) and prolactin (PRL), are composed of ovoid, elongated, and angular cells which demonstrated interdigitating processes and junctional complexes. The majority of the cells were essentially agranular, but two types of granulated cells were identifiable. One class of granulated cells contained moderate to sparse populations of round dense‐cored granules measuring up to 250 nm in diameter. Rod‐shaped to filamentous mitochondria with an electron‐dense matrix were characteristic of a second class of granulated cells with pleomorphic granules of various sizes and electron densities. Images of exocytotic release of the round dense‐cored granules were frequently seen, but were not observed with the pleomorphic granules, many of which were judged to be lysosomes. Superimposition immunocytochemistry revealed hormones only in the granulated cells with round to ovoid granules. Morphometry indicated that hormone specific subpopulations of tumor cells can be identified since PRL secretory granules were significantly smaller than GH secretory granules (149 ± 6 nm for PRL versus 221 ± 9 nm for GH, P < 0.001). The vast majority of immunopositive cells contained only GH or PRL, but a few were observed containing both hormones. Ovoid to irregular‐shaped nuclei, large lipid inclusions, numerous free ribosomes and polyribosomes, moderate development of the rough endoplasmic reticulum, and prominent Golgi profiles were characteristics of all cell types. Irrespective of the presence or absence of cytoplasmic granular elements, particles resembling viruses were encountered in many tumor cells, and these frequently appeared to be budding into the cisternae of the endoplasmic reticulum.
Ultrastructural and biochemical effects of D‐penicillamine on mouse hepatocytes
Authors: Walter Robert J. , Tandler Bernard , Hoppel Charles L. 
Published: February 2005

AbstractThe ultrastructural and oxidative metabolic effects of D‐penicillamine were examined in hepatocytes of mice fed various concentrations of the drug for periods up to 11 days. In virtually all animals studied, membranous material in the form of whorls, sheaves, and irregular networks was observed in some bile canaliculi. In several mice a few mitochondria were substantially enlarged, with diameters of 4‐6 μm. In other animals some mitochondria became quite elongated, measuring 10 μm in length but only 0.5 μm in width. Certain mitochondria had small deposits of dense material in their outer compartment. Lysosomes contained numerous small dense particles; aggregates of these particles were also observed free in the cytosol. Despite these alterations, the vast majority of hepatocytes showed no changes whatsoever. Study of isolated hepatic mitochondria derived from the experimental animals showed no alterations in oxidative metabolism. It may be concluded that, unlike other copper‐chelating agents, D‐penicillamine has little significant morphological and biochemical effect on mouse hepatocytes, even when its concentration exceeds standard clinical dosages.
Responses of mouse spleen morphology to the growth of subcutaneously injected virally transformed cells
Authors: Nutter Robert L. , Gridley Daila S. , Slater James M. , McMillan Paul J. 
Published: February 2005

AbstractThe changes in the fractional volume of six structural components in the spleens of Balb/C mice injected with Herpes simplex virus Type 2‐transformed cells (H238 tumor cells) were quantitated during progressive tumor growth. Spleen sterology was performed at three time intervals during the early stages of tumor development. The results revealed that the volume of the compact myeloid tissue and reaction centers of lymphoid nodules increased about four‐ to five‐fold from 10 to 33 days after H238 tumor cell injection. A progressive increase was also seen in the red pulp volume. Although an increase in volume of the marginal zones around the lymphoid nodules was evident early during the test period, by day 33 the mean value was similar to the control value. These results indicate that the spleen undergoes significant morphological changes in three splenic components during progressive growth of a tumor produced by subcutaneous injection of a virally‐transformed cell line.
Necrotic extrafusal muscle fibers of the dystrophic mutant mouse: The ultrastructure of the myoneural junction
Authors: Ontell Marcia , Haller Edward 
Published: February 2005

AbstractAt 28 days postpartum, the extensor digitorum longus muscle of the dy2J mutant mouse contains a population of myofibers which exhibit coagulation necrosis for ˜90% of their length. Using the electron microscope, motor endplates were found on more than half of the necrotic fibers studied, occurring in mildly, moderately, and severely necrotic regions of these fibers. The ultrastructural features of the axonal terminals did not vary with the condition of the fiber segment at which the endplate occurred. No morphological criteria could be established for distinguishing between the axonal terminals of necrotic fibers and those of “healthy” fibers in the dystrophic animal. The principle morphological changes at motor endplates of necrotic fibers involved not the axonal terminal, but the muscle fiber itself.This study demonstrates that the necrotic myofibers, which are present at the onset of the first clinical symptoms of murine dystrophy, are innervated. Therefore, necrosis is not precipitated by structural denervation. Furthermore, observations of motor endplates on mildly, moderately, and severely necroctic regions of the myofibers indicate that regional changes along the necrotic fiber 's length are not a function of distance from the motor endplate.
Muscle spindle supply to the bovine jaw muscles
Authors: Kubota Kinziro , Komatsu Shigeru , Nakamura Mitsutaka , Masegi Toshiaki 
Published: February 2005

AbstractThe jaw‐closing muscles of two bovine fetuses average 1,177 muscle spindles on one side of the face: 549 in the masseter, 433 in the temporalis, 192 in the medial pterygoid, and three in the lateral pterygoid. The jaw‐opening muscles have no spindles.
Accumulation of CPC‐precipitable material at apical cell surfaces during formation of the optic cup
Authors: Robert. Hilfer S. , Yang Jyh‐Jla W. 
Published: February 2005

AbstractAccumulation of extracellular material at the apical surfaces of cells in the optic vesicle was studied by precipitation with cetylpyridinium chloride (CPC) and scanning electron microscopy. Treatment at low salt concentration to preserve all precipitable material indicated an initial appearance of surface material at the time that the retinal primordium first formed. The amount of precipitate increased as the optic cup formed, particularly at the margins of the cup. Stability of the precipitate during subsequent washing at higher salt concentrations suggested that the apical cell surface material contained highly acidic glycosaminoglycans. The greatest resistance to extraction occurred during the period in which invagination was most pronounced.
Muscle sarcomere length following passive jaw opening in the rabbit
Authors: Hertzberg S. R. , Muhl Z. F. , Begole E. A. 
Published: February 2005

AbstractSarcomere lengths were measured microscopically in formalin‐fixed jaw muscles of 14 rabbits divided into two groups; jaw open, and jaw closed. The measurements were compared by means of a nested analysis of variance. The sarcomeres of the jaw open group were longer in the masseter and temporalis muscles (jaw elevators) and shorter in the digastric muscle (jaw depressor) than were those of the jaw closed group. In the jaw closed position, sarcomeres in the deep portion of the masseter muscle become markedly shorter than those in the superficial part of the muscle. The values for sarcomere length in the masseter muscle of the jaw open group and the digastric of the jaw closed group are near the top of the ascending limb of isometric length‐tension relation for the rabbit digastric muscle.
Ependymal astrocytes in the frog cerebellum
Authors: Korte Gary E. , Rosenbluth Jack 
Published: February 2005

AbstractWe have examined the ependymal astrocytes of the frog cerebellar cortex in thin sections and freeze‐fracture replicas. The somata border the fourth ventricle and give rise to basal processes whose daughter branches cross the molecular layer and terminate as subpial endfeet. Irregular lamellar appendages arise from the basal processes and their branches. In the molecular layer the appendages selectively ensheath apposed parallel fiber boutons and Purkinje cell dendritic spines. Other appendages ramify throughout the neuropil, some contributing to extensive pericapillary sheaths.Freeze‐fractured ependymal astrocyte plasma membrane consistently has a greater concentration of intramembranous particles (IMPs) and IMPs of larger mean size than neuronal plasma membrane in the same replicas. Like the astrocytes of the mammalian central nervous system, frog ependymal astrocytes form numerous gap junctions with each other. However, orthogonal arrays of IMPs (“assemblies”) were not observed.Ependymal cells in the frog cerebellum combine the morphology, and probably the functions, of both ependymal cells and astrocytes.
Anatomy of the nasal‐pharyngeal airway of experimental animals
Authors: Schreider Jay P. , Raabe Otto G. 
Published: February 2005

AbstractSilicone rubber casts were prepared of the nasal, pharyngeal and laryngeal regions of two rats, a rhesus monkey, and three beagle dogs and one for each species selected for detailed measurements. Cross‐sections of the casts were made and the area and perimeter of each section measured using an image analyzing computer. Considerable anatomical differences were found between the species. Some of the differences, such as the sharp bend in the nasopharynx of the monkey, could be related to normal posture. One of the main differences was the greater complexity of the turbinate region of the dog as compared to the corresponding area of the monkey.