bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural and functional effects of chronic endogenous stimulation of thyroid cells by thyrotropin
Authors: Krupp Patricia P. , Kavolius J. P. , Golstein J. , Nève P. 
Published: February 2005

AbstractFollowing total thyroidectomy, a small quantity of thyroid tissue was transplanted to the spleen in order to study thyroid tissue subjected to chronically elevated levels of endogenous thyrotropin (TSH). Plasma thyroxine (T4) and TSH levels were monitored and correlated with ultrastructural studies of the tissue over a 32‐week experimental period. The effects of administration of an iodine‐poor diet, an exogenous acute dose of TSH, and suppression of endogenous TSH through thyroxine administration were studied in order to evaluate the plasticity of the experimental model.Plasma T4 decreased after the first week and remained at approximately one half of the initial value until 12 weeks. Plasma TSH increased to a high of 6,220 ng/ml after 6 weeks and gradually declined to one half of that value. The transplanted tissue remained functional throughout the experimental period. The number of pseudopods decreased, and irregularly shaped, dense bodies increased from the time of surgery until 12 weeks later. Administration of an acute dose of TSH at this time resulted in obvious mitotic activity and the formation of numerous pseudopods. The tissue also maintained the ability to take up radioactive iodine and to iodinate thyroglobulin. Inhibition of TSH secretion through T4 administration from the time of surgery did not affect viability. Some cellular hypertrophy persisted after 32 weeks although TSH and T4 had returned to normal.This study has shown that thyroid tissue remains viable, functional, and experimentally alterable throughout an extended period of chronic stimulation by endogenous TSH, and that it has the reserve capacity to secrete normal levels of T4 at the end of this experimental period.
An ultrastructural study of the effect of a diabetogenic dose of alloxan on the secretory ameloblasts of the rat incisor
Authors: Karim Algernon C. 
Published: February 2005

AbstractThe effect of a single diabetogenic dose of alloxan on the ameloblasts of enamel secretion was investigated in rat incisor teeth prior to the onset of diabetes mellitus. This was compared with tissue from animals that were sacrificed at the onset of diabetes, and with tissue from animals that had been diabetic for 1 month. Male Sprague‐Dawley rats were given a single subcutaneous injection of alloxan at a dose of 150 mg/kg body weight; and the animals were sacrificed at 45 minutes, 2 hours, 24 hours, 48 hours and 29 days after injection. At the electron microscope level the following changes were observed. There was an early accumulation of secretion granules in the vicinity of the Golgi apparatus and within the proximal portion of Tomes' process. These accumulations were present at the onset of diabetes, 24 hours later. At 2 hours after injection a space appeared between the plasma membrane around Tomes' process and the interrod material. This space widened with time, and at 24 hours after injection it became continuous with enlarged intercellular spaces between the proximal portions of Tomes' processes. The widening of the intercellular space was restricted to the area above the distal cell web. At the onset of diabetes this compartment of the cells was similar to that of the control samples. Extracellular material which appeared to be the secretory product of the ameloblast was observed at two sites. On one occasion this material was seen in the wide intercellular spaces between the proximal portions of Tomes' processes 24 hours after injection. It was also seen at the onset of diabetes in the intercellular space at the level of the Golgi apparatus. The changes in the animals that had been diabetic for 1 month were a scarcity of secretion granules within Tomes' processes and an abnormal accumulation of secretion granules within the supranuclear and infranuclear compartents.This study has shown that the toxic effect of alloxan persists up to the time of onset of diabetes mellitus. However, since different morphological changes were observed during diabetes mellitus, it is suggested that the changes caused by diabetes are a separate entity, initially superimposed on and later replacing the acute, toxic effect of the drug.
Circadian variation in the urinary excretion of electrolytes and trace elements in men
Authors: Kanabrocki Eugene L. , Scheving L. E. , Olwin J. H. , Marks G. E. , McCormick J. B. , Halberg F. , Pauly J. E. , Greco J. , De Bartolo M. , Nemchausky B. A. , Kaplan E. , Sothern Robert 
Published: February 2005

AbstractThree‐hour urine specimens were collected over a period of 27 hours from 11 healthy adult male subjects. Each specimen was analyzed for Na, K, Ca, Mg, and Zn using atomic absorption spectrophotometry. Each sample was also dialyzed, pH 7.35, and subsequently analyzed for Na, K, P, Ca, Mg, Zn, Fe, Pb, Al, Ni, Cu, Mo, Hg, Cr, Cd, and Mn using a multielemental argon‐plasma emission system. The data were evaluated on conventional time plots (chronograms) and as computer‐determined “cosinor” plots. A population circadian rhythm with a statistical significance was detected for total Na, K, Ca, and Mg, and for nondialyzable Na, K, P, Ca, Zn, and Mo. For almost every element studied the increase from lowest to highest 3‐hour group mean along the 24‐hour time scale was more than 100%. The 24‐hour excretion of Na, K, Ca, Mg, and Zn appeared in good agreement with the so‐called “normals.” The nondialyzable levels of Fe, Pb, Al, Ni, Cu, Mo, Hg, Cr, Cd, and Mn were similar to the total urinary excretions reported in the literature.
Morphological changes in the hypothalamic arcuate nucleus and median eminence in the golden hamster during the neonatal period
Authors: Lamperti Albert , Mastovich John 
Published: February 2005

AbstractThe purpose of the present investigation was to study the ultrastructure of the arcuate nucleus (ARC) and median eminence of hamsters on days 1–15 of the neonatal period. From days 1–6, the neurons of the ARC had large nuclei and a small amount of cytoplasm which contained polysomes, mitochondria, RER, lysosomes and Golgi complexes. From days 7–15 there was an increase in the amount of cytoplasm as well as more extensive Golgi complexes and RER. Astrocytes were the predominant glial component in both the ARC and median eminence. Astrocytic processes were in juxtaposition to unmyelinated axons, dendrites, and synapses. Axodendritic and axosomatic synapses containing clear vesicles were observed in the neuropil on day 1. There was an increase in the number of dense‐core vesicles in the axonal endings beginning on day 4.Concomitantly, there were increasing numbers of clear and dense‐core vesicles (64–70 nm) in terminals of the external layer of the median eminence, whereas larger dense‐core vesicles (105–140 nm) were distinguishable by day 10 immediately dorsal to the external layer. The capillaries of the median eminence were composed of nonfenestrated endothelium from days 1–9. Fenestrae began to appear about day 10. Ependymal cells lining the third ventricle had pinocytotic vesicles, microvilli, and bleb‐like protrusions on their apical surfaces. Ependymal processes were adjacent to nerve processes in the neuropil of the ARC and in the external layer of the median eminence, where they contacted the perivascular space.Two types of supraependymal cells were seen in animals throughout the neonatal period. One resembled a neuron which sent processes along the ependymal surface and often between cells. The second type was similar to a macrophage. The results of this study demonstrate the maturation of the neural elements in the ARC/median eminence area of the neonatal hamster.
The distribution of actin in cultured ovarian granulosa cells
Authors: Batten Bruce E. , Anderson Everett 
Published: February 2005

AbstractOvarian granulosa cells grown on glass coverslips were split by a “sandwich” technique. Using this technique we describe a complex filamentous network in the cytoplasm of cultured granulosa cells that was composed of a branching and anastomosing lattice of filaments 20–40 nm in diameter. Since filament identification impossible on the basis of size, split cells were decorated with S‐1 fragments of rabbit skeletal muscle myosin. It was readily apparent that the major constituent of the filamentous lattice was actin. Actin was organized in large bundles in which individual filaments were longitudinally aligned. Actin was also observed organized in a loose network throughout the remainder of the cytoplasm. Actin appeared to be intimately associated with organelle and plasma membranes. Coated pits were also a site of actin‐filament interaction. Filament polarity was generally away from the membrane with which filaments were associated.
Occlusion and reformation of the rat uterine lumen during pregnancy
Authors: Welsh Alerick O. , Enders Allen C. 
Published: February 2005

AbstractImplantation sites were obtained from rats at various stages of pregnancy and were studied by light microscopy and scanning electron microscopy. Early in pregnancy the uterine luminal epithelium and the decidual cells in the implantation site formed an implantation chamber containing the conceptus. The epithelial cells lining the chamber and the mouth of the chamber degenerated, and the uterine lumen that was mesometrial to the conceptus was obliterated such that the uterine lumen became discontinuous, and the luminal epithelia of intersite areas were isolated. As the conceptus continued to grow, the decidua‐conceptus unit bulged into the intersite areas and was partially covered by an epithelium that eventually became discontinuous and degenerated. Once this had occurred, the luminal epithelium of the intersite areas reestablished contact antimesometrial to the decidua‐conceptus unit, and the uterine lumen was again continuous. However, the epithelium lining the lumen was not complete in the mesometrial region because of the vascular connections between the uterine stroma and the placenta. Factors influencing the restructuring of the uterine luminal epithelium were discussed.
The embryonic origins of avian cephalic and cervical muscles and associated connective tissues
Authors: Noden Drew M. 
Published: February 2005

AbstractThe objective of these experiments was to determine the embryonic origins of craniotacial and cervical voluntary muscles and associated connective tissues in the chick. To accomplish this, suspected primordia, including somitomeres 3–7. somites 1–7, and cephalic neural crest primordia have been transplanted from quail into chick embryos. Quail cells can be detected by the presence of a species‐specific nuclear marker. The results are summarized as follows:
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These results indicate that muscles associated with branchial arch skeletal structures are derived from paraxial mesoderm, as are all other voluntary muscles in the vertebrate embryo. Thus, theories of vertebrate ontogeny and phylogeny based in part on proposed unique features of branchiomeric muscles must be critically reappraised. In addition, many of these cephalic muscles are composites of two separate primordia: the myogenic stem cells of mesodermal origin and the supporting and connective tissues derived from the neural crest or lateral plate mesoderm. Defining these embryonic origins is a necessary prerequisite to understanding how the mesenchymal primordia of cephalic muscles and connective tissues interact to form patterned, species‐unique musculoskeletal systems.
Abnormal distribution of fiber types in the slow‐twitch soleus muscle of the C57BL/6J DY2J/DY2J dystrophic mouse during postnatal development
Authors: Ovalle W. K. , Bressler B. H. , Jasch L. G. , Slonecker C. E. 
Published: February 2005

AbstractThe postnatal development of extrafusal fibers in the slow‐twitch soleus muscle of genetically dystrophic C57BL/6J dy2J/dy2J mice and their normal age‐matched controls was investigated by histochemical and quantitative methods at selected ages of 4, 8, 12, and 32 weeks. The majority of fibers in the soleus consisted of two kinds, fast‐twitch oxidative‐glycolytic (FOG) and slow‐twitch oxidative (SO), according to reactions for alkaline‐stable and acid‐stable myosin ATPase and the oxidative enzyme, NADH‐tetrazolium reductase. A minor population of fibers, stable for both alkaline‐ and acid‐preincubated ATPase, but variable in staining intensity for NADH‐TR, were designated “atypical” fibers.With age, the normal soleus exhibited a gradual increase in the number and proportion of SO fibers and a reciprocal, steady decline in the percentage of FOG fibers. Atypical fibers were numerous at 4 weeks, but were substantially diminished at later ages. Since total extrafusal fiber number remained relatively constant between the periods examined, this change in relative proportions reflects an adaptive transformation of fiber types characteristic of normal postnatal growth.A striking alteration in the number and distribution of fiber types was associated with the dystrophic soleus. At 4 weeks an 18% reduction in total fiber number was already noted. Subsequently, by 32 weeks a further 22% diminution in overall fiber number had occurred. With age, the absolute number and proportion of dystrophic SO fibers were drastically reduced. In contrast, the percentage of dystrophic FOG fibers increased significantly while their absolute numbers between 4 and 32 weeks remained relatively constant. Atypical fibers in the dystrophic solei were found in elevated numbers at all age groups, particularly at 12 weeks. They may, in part, represent attempts at regeneration or an intermediate stage in fiber‐type transformation. Microscopically, both of the major fiber types appeared affected, albeit differently, by the dystrophic process. We suggest that a failure or retardation in the normal postnatal conversion of fiber types within the soleus muscle occurs in this murine model for muscular dystrophy.
Kinematics of cranial vault growth in rabbits
Authors: Alberius P. , Selvik G. 
Published: February 2005

AbstractTo characterize mathematically the spatial rearrangement of cranial vault bones of the rabbit during growth, a longitudinal study was undertaken from age 4–20 weeks. Initially, at least three nonlinear tantalum bone markers were implanted in the parietal, frontal, and the combined nasal bones. Thereafter, the animals were followed regularly with roentgen stereo‐photogrammetrical analysis. The parietal bones were found to rotate laterally upward (3°), while the frontal bones rotated downward (2°) relative to their contralaterals. The frontal bones rotated rostrally upward (12°) and outward (3°) as well as laterally downward (5°) in relation to the parietal bones. Due to the morphology of the rabbit head, the examination positioning used in this study, and the direction of the growth process, growth at the coronal suture correlated fairly well with longitudinal axis translations; but the growth at the frontonasal suture relative to the frontal bones was directed about 45° downward. This points to the importance of the bone‐marker positioning, so that their connecting line is directed along the axis of growth. Also, this approach makes it possible to obtain new information on the development and treatment of craniofacial aberrations.
Tridimensional architecture of the golgi apparatus in the atrial muscle cell of the rat
Authors: Rambourg A. , Segretain D. , Clermont Y. 
Published: February 2005

AbstractThe tridimensional structure of the Golgi apparatus of atrial muscle cells has been studied in thin and thick sections with low‐and high‐voltage electron microscopes. Cardiac tissue was inpregnated with osmium, stained to demonstrate phosphate activity (i.e., nicotinamide adenine dinucleotide phosphatase or NADPase; thiamine pyrophosphatase or TPPase; cytidine monophosphatase or CMPase) or postfixed and stained with potassium ferro‐cyanide‐reduced osmium. At low power, in thick (3–10 μm) sections, the cis‐osmiophilic element and the NADPase‐and the TPPase‐positive saccules each appeared as a continuous irregular ribbon that formed, at the two poles of the nucleus, two conical masses connected to each other by beltlike bands encircling the nucleus. At higher magnifications, the continuous Golgi apparatus showed saccular regions along its length connected by short intersaccular tubular regions. In the saccular regions, the following five superimposed elements formed a stack: (1) the cis‐osmiophilic network of anastomosed tubules; (2) a chromophobic, dilated saccule perforated with numerous pores; (3) a thin NADPase‐positive saccule showing few pores; (4) a thin TPPase‐positive saccule perforated with numerous minute pores; and (5) a CMPase‐positive trans‐element that showed saccular and tubular regions and was often partly separated from the overlying saccule. In the intersaccular tubular regions, membranous tubules connected and bridged saccules of two adjacent saccular regions. Secretory granules usually appeared in this region as dilations of the tubules connected to all elements of the Golgi stack except the cis‐osmiophilic element.
Light and electron microscopic examination of the mature decidual cells of the rat with emphasis on the antimesometrial decidua and its degeneration
Authors: Welsh Alerick O. , Enders Allen C. 
Published: February 2005

AbstractRat gestation sites were obtained on days 10 through 16 of normal pregnancy. Light and electron microscopic examination of day‐10 sites revealed a consistent complex pattern of stromal cell morphologies. Six distinct regions were identified: an antimesometrial region of epithelioid decidual cells that form the gestation chamber containing the embryo and extraembryonic membranes; an abembryonic antimesometrial decidual region, the decidual crypt, where the cells are separated by large extracellular spaces; a mesometrial region with granule‐containing cells and mesometrial decidual cells; a region of spiny cells that are lateral to the antimesometrial decidual cells and continuous with the mesometrial decidual cells; and a region of undifferentiated stromal cells adjacent to the myometrium. Between days 12 and 16, the antimesometrial decidua becomes thinner and is eventually sloughed into the newly formed uterine lumen. The role of the antimesometrial decidual cells is discussed with reference to trophoblast invasiveness, protein synthesis, and especially remodeling of the gestation chamber. Differences between decidua and deciduoma are considered.
Structure of taste buds in foliate papillae of the rhesus monkey, Macaca mulatta
Authors: Farbman Albert I. , Hellekant Göran , Nelson Adrienne 
Published: February 2005

AbstractTaste buds in foliate papillae of the rhesus monkey were examined by electron microscopy. Three distinct cell types were identified. Type I cells were narrow elongated cells containing an oval nucleus, bundles of intermediate filaments, several Golgi bodies, and characteristic apical membrane‐bounded dense granules. These cells exhibited morphological variations: some had a moderately dense cytoplasm, perinuclear free ribosomes, and flattened sacs of rough endoplasmic reticulum; others had a more lucent cytoplasm, dilated irregular rough endoplasmic reticulum, lysosome‐like dense bodies, and lipid droplets. Type II cells typically contained a spherical, pale nucleus, a prominent nucleolus, supranuclear and infranuclear Golgi bodies, mitochondria with tubular cristae, and one or two centrioles. This cell type, too, showed some variation in the relative amounts of ribosomes and smooth endoplasmic reticulum, which varied inversely with each other. Type III cells were characterized by a clear apical cytoplasm essentially devoid of ribosomes and containing microtubules. In a few type III cells, the peri‐ and infranuclear regions contained many ribosomes and some rough endoplasmic reticulum. In most Type III cells, there were large numbers of dense and clear vesicles in the peri‐ and infranuclear regions; some of the vesicles were grouped in synapse‐like arrangements with adjacent nerves. The morphological variations exhibited by all three cell types could be accounted for by age differences in each of the cells. This would be consistent with the notion that cell renewal occurs in each of the three cell populations.
Ultrastructure of sertoli‐cell penetrating processes found in germ cells of the golden‐mantled ground squirrel (Spermophilus lateralis)
Authors: Vogl A. W. , Soucy L. J. , Foo V. 
Published: February 2005

AbstractWe have studied the ultrastructure of Sertoli‐cell processes that extend into developing germ cells of the ground squirrel (Spermophilus lateralis). In other mammals it is speculated that these processes anchor germ cells to the seminiferous epithelium and transfer materials between Sertoli and germ cells. In the ground squirrel, Sertoli‐cell projections first appear in round spermatids and consist of regions containing numerous mitochondria and intermediate filaments together with areas composed mainly of a fine filamentous matrix. Also present are what may be desmosomelike junctions with adjacent germ cells. During spermatogenesis, numerous changes in the penetrating processes and their internal composition occur. Especially significant are those occurring during the movement of residual cytoplasm basaly over spermatid heads: some Sertoli‐cell processes contain microtubules, mitochondria and vesicular elements, but also present are regions that lack organelles and appear simply as thin lamellae of cytoplasm that line cavernous invaginations of the germ cell. Coated vesicles and pits are present in processes and adjacent germ‐cell regions at all stages of spermatogenesis. Our observations are consistent with the suggestions that Sertoli‐cell processes have an attachment function and that they also may facilitate the movement of residual cytoplasm into the epithelium. Further, they indicate that these structures might be involved with receptor‐mediated edocytosis.
Retinofugal projections of the big brown bat, Eptesicus fuscus and the neotropical fruit bat, Artibeus jamaicensis
Authors: Cotter John R. 
Published: February 2005

AbstractRetinal connections were studied in Eptesicus fuscus and Artibeus jamaicensis using anterograde axonal degeneration and autoradiographic techniques following unilateral enucleations and uniocular injections of radioactive amino acids. Although each retina projected bilaterally to the brainstem, the number of silver grains in the emulsion of autoradiographs indicated that nearly all fibers in the optic nerve entered the contralateral optic tract. Ipsilaterally, a major portin of the projection ended in the suprachiasmatic nucleus; caudal to the suprachiasmatic nucleus, the amount of label was so small that individual silver grains were counted to determine the location and quantity of lebel in other ipsilateral nuclei. In both species the retinal projection terminated bilaterally in the suprachiasmatic, dorsal lateral geniculate, ventral lateral geniculate, and pretectal olivary nuclei and contralaterally in the posterior pretectal nucleus, superficial gray layers of the superior colliculus, and nuclei of the accessory optic system. In Eptesicus the projection to the nucleus of the optic tract ended contralaterally, and in Artibeus it ended in this nucleus bilaterally. The results of this study revealed a basic theme in the optic projection of the two ecologically different microchirop. terans. The results differed, however, in that the projection was larger and visually related nuclei were better developed in Artibeus. Such variations are presumed to relate to eye size and the relative use of vision by the two chiropterans.