bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine structure of the adrenal gland in the duck (Anas platyrhynchos)
Authors: Cronshaw James , Holmes W. N. , Loeb S. L. 
Published: February 2005

AbstractAdrenal glands of the domestic duck (Anas platyrhynchos) were fixed in formaldehyde‐glutaraldehyde for light and electron microscopical examination. Each gland is encapsulated by a layer of connective tissue and consists of two major secretory cell types, the interrenal cells and the medullary cells. In section, the medullary cells appear as islands of tissue dispersed throughout the gland. The interrenal cells are characterized by numerous lipid droplets and abundant mitochondria having mainly tubular cristae. They have an extensive Golgi apparatus, moderate amounts of smooth endoplasmic reticulum and a lesser amount of rough endoplasmic reticulum. Lipid droplets and mitochondria in interrenal cells were seen frequently in association with the endoplasmic reticulum. Adjacent interrenal cells had numerous regions of pentalaminar fusion and intermediate junctions.Medullary cells were characterized by a large population of electron opaque neurosecretory granules. These cells contained fewer mitochondria and cisternae of endoplasmic reticulum than the interrenal cells. In many cases the medullary cells and interrenal cells were closely juxtaposed and were separated by a thin band of extracellular matrix.
The ciliary pattern of the parietal layer of Bowman's capsule
Authors: Webber W. A. , Lee J. 
Published: February 2005

AbstractThe parietal layer of Bowman's capsule in man and rat has been examined by transmission and scanning electron microscopy. In both species, cilia were found to be present in a regular pattern occurring one per cell. The cilia differed in length between the immature and mature human kidney, but were consistently located near the edge of the cell nucleus. Since they are not numerous enough to have a significant propulsive role, we have postulated that they may have some other specific function. In addition to the cilia, microvilli were regularly observed on the surface of the parietal cells. They tended to be more numerous along the margins of the epithelial cells and, in contrast to the cilia, their pattern was highly variable. This variability probably indicates that they are transitory structures which can be increased or decreased in response to as yet unknown stimuli.
Electron microscopic studies of the state of myosin aggregation in the vertebrate smooth muscle cell
Authors: Bois Richard M. , Pease Daniel C. 
Published: February 2005

AbstractGlycol dehydration followed by rehydration prior to conventional fixation appears to demonstrate the essential identity of the thick filaments observed in unfixed, glycol dehydrated and conventionally fixed smooth muscle. Observed differences in the solubilities of actin and myosin filaments also suggest that the thick filaments of smooth muscle are not formed by the apposition of actin filaments or by the deposition of myosin upon actin filaments. Evidence that the thick filaments of smooth muscle are not formed by an unnatural aggregation of smaller myosin aggregates or by the dissociation of myosin “ribbons” during tissue preparation is also reported. Examinations of smooth muscle contracted or relaxed by pharmacological agents appear to indicate that the myosin content of smooth muscle is aggregated into filaments in both the contracted and relaxed cell.
Correlation of serum gonadotropins, ovarian and uterine histology in immature and prepubertal rats
Authors: Knudsen J. F. , Costoff A. , Mahesh V. B. 
Published: February 2005

AbstractOvarian and uterine morphological changes were examined in the maturing Holtzman rat, ages 22–40 days, using routine histological procedures. These findings were then correlated with serum follicle stimulating hormone (FSH) and luteinizing hormone (LH), in an effort to trace the sequence of events involved in the onset of puberty (i.e., the initiation of cyclicity) which occurred most consistently in our rats at 38 days of age. Ovaries exhibited no significant weight increases prior to day 36. However, microscopic changes became apparent as early as day 30, and continued to day 38, the day of the gonadotropin surge. During this time interval, the proportion of large type 6‐7 (potentially estrogen secreting follicles) increased dramatically relative to non‐antrum containing follicles. An increasingly hypertrophied and well differentiated theca interna of the larger follicles was also characteristic of this age interval. Closely paralleling the sequence of follicular maturation, quantitative and qualitative increases in all layers of the uterus occurred. As early as day 32, the luminal epithelium had increased some three to four‐fold over earlier age groups. Similarly, the stromal endometrium and myometrium increased significantly at this time. Further increments occurred through day 34, with a leveling off at this time.Serum FSH showed no significant increases prior to day 38, at which time levels increased some two‐fold over previously existing levels. In contrast, LH remained tonic until days 34 and 36, at which time subthreshold elevations occurred. On day 38, LH rose some 40‐fold over pre‐existing levels. Serum prolactin followed a similar pattern; levels became detectable at 33 days of age with marked elevations seen on day 35 and on day 38 of age.From quantitative and qualitative analysis of ovarian and uterine morphology with subsequent correlations to serum gonadotropins over the maturing process, we conclude that the ovary possibly acts as a “Zeitgeber” for the gonadotropin surge and ovulation.
Human muscle spindles: Microfilaments in the group IA sensory nerve endings
Authors: Kennedy William R. , Def. Webster Henry , Yoon Kwon Sang , Jean Dou H. 
Published: February 2005

AbstractThe fine structure of the group IA sensory nerve endings from normal human muscle spindles was studied in transverse and longitudinal sections. Two arrangements of microfilaments, approximately 75 Å in diameter, were found in each of ten spindles examined. The first was a central aggregate of densely packed filaments. The aggregates were partly surrounded by mitochondria, and were oriented parallel to the longitudinal axis of the sensory ending as it encircled the intrafusal muscle fiber. Individual aggregate filaments of glycerinated endings appeared to react with heavy meromyosin. The second arrangement was a filamentous network in the periphery of the sensory ending profiles. These microfilaments approached and appeared to merge with the surface membrane. They resembled the microfilaments that others have described in growth cones of cultured neurons. Both types of microfilaments are thought to be involved in changing the shape of the sensory endings during stretch and relaxation of the spindle.
The effect of proteolytic enzymes and hyaluronidase on the intracellular β‐ and γ‐metachromatic granules and the matrix of rat epiphyseal cartilage
Authors: Hirschman Albert , McCabe Dorothy M. 
Published: February 2005

AbstractThe effects of trypsin, chymotrypsin, papain, pronase, cartilage protease and hyaluronidase on the staining of fresh epiphyseal cartilage in 0.01% toluidine blue at pH 4 was studied. Treatment with these enzymes resulted in a loss of the β‐ and γ‐metachromatic granules in the cells, and an intensification of the staining in the matrix of the lower hypertrophic zone. Treatment with collagenase also resulted in a loss of the β‐ and γ‐metachromatic granules, but did not appreciably intensify the staining of the matrix. Carboxypeptidase A, ribonuclease and bovine serum albumin, globulins, and globin had little or no effect.
The effect of ruthenium red and concanavalin A on the vitelline surface of fertilized and unfertilized rabbit ova
Authors: Gordon Mildred , Fraser Lynn R. , Dandekar Pramila V. 
Published: February 2005

AbstractFertilized and unfertilized rabbit ova were exposed to ruthenium red with the zona intact or after machanical removal, for the demonstration of mucopolysaccharides on the surface coat. Ova were also exposed to Concanavalin A. Ruthenium red bound strongly to elements of the zona and increased the opacity of the plasmalemma. There was no notable change in staining of the vitellus following fertilization. Although there were ruthenium red stained bodies resembling cortical granules in crypts in the plasmalemma, there was no evidence for cortical granule extrusion of mucopolysaccharides. The Concanavalin reaction was seen over both unfertilized and fertilized ova, demonstrating receptors for terminal α‐D‐mannopyranosyl, α‐D‐glycopyranosyl, β‐D‐fructofuranyosyl residues. The deposit on the fertilized egg surface was enormously enhanced indicating a change in the distribution of receptor sites.
Immunochemical staining of the rat adenohypophysis in organ culture
Authors: Pakurar Alice S. , Kahn Raymond H. , Conklin James L. 
Published: February 2005

AbstractRat anterior pituitaries were cytologically studied following cultivation in organ culture, with and without the addition of hypothalamic and cortical extracts. Although five distinct cell types could be identified with classical stains in the uncultivated glands, the peroxidase‐labeled antibody technique (using antibodies against STH, LTH, FSH, LH and TSH) showed that not all of the immune‐specific cell types were being identified with the classical stains. This discrepancy was magnified following culture as chromophilic cells seen with classic stains decreased in number with an increase in culture time. The peroxidase technique, however, revealed that all cells remained constant in type and number regardless of time in culture. While the addition of either hypothalamic or cortical extract to the culture medium produced cytological alterations demonstrated by the classical dyes, the antibody technique showed no such alterations. Such a comparison of staining techniques emphasizes the hazards of relying solely on histological procedures to reveal the hormonal activity of the pituitary gland.
Reciprocal synapses between cholinergic axons and small granule‐containing cells in the rat cardiac ganglion
Authors: Yamauchi Akio , Yokota Reiko , Fujimaki Yoko 
Published: February 2005

AbstractElectron microscopy of the rat cardiac ganglion shows occurence of small granule‐containing cells that form reciprocal synaptic junctions with cholinergic terminals. At the synaptic junctions which are from axon to granule‐containing cell, the intraaxonal vesicles are clustered against the junctional axolemma, but dense‐cored vesicles in the postynaptic cell do not cluster towards the membrane densities in these synapses. By contrast, the synaptic zone polarized in the opposite direction shows an absence of axonal vesicles in close proximity to the postsynaptic axolemma, but there is a marked aggregation of dense‐cored vesicles towards the presynaptic specializations of granule‐containing cells. The synaptic zones are multifocal rather than bifocal, and the minimal distance separating each synaptic zone is about 0.3 μ. These findings may indicate that cholinergic excitation of some or all granule‐containing cells causes a reciprocal inhibition of one or more cholinergic terminals.
SEM preparation and observations of the hen's oviduct
Authors: Bakst M. , Howarth B. 
Published: February 2005

AbstractThe surface patterns of the oviduct of Gallus domesticus were examined by scanning electron microscopy (SEM) using several preparatory techniques. Ciliated epithelial cells predominate throughout the oviduct with nonciliated cells approaching an equal proportion in the magnum and isthmus. Short, randomly oriented mucosal folds which characterize the infundibulum increase in height and longitudinal orientation as they approach the magnum. Here and in the isthmus they broaden and become dimpled with glandular apertures. The folds narrow again in the uterus and vagina. Cryofracture followed by SEM demonstrate the deeper mucosal folds and submucosal tubular system.
Intestinal mucosa of the platypus, Ornithorhynchus anatinus
Authors: Krause William J. 
Published: February 2005

AbstractThe intestinal mucosa of the platypus takes the form of numerous transverse surface folds. These folds are made up of a lamina propria covered by pseudostratified epithelium which lies on a thick modified basement membrane. The cells of the intestinal epithelium consist of columnar cells which generally resemble typical intestinal epithelium and cuboidal cells, which are undifferentiated in appearance, show few organelles and possess an electron lucent cytoplasm. Numerous desmosomes are found between the adjacent cell membranes of both cell types. Villi are absent and appear to be represented by the large surface folds.Intestinal glands are composed of columnar epithelium similar to that found in the intestinal glands of other mammalian species. Groups of these glands drain into common tubular ducts which follow a tortuous course and empty into the intestinal lumen between the surface folds.The peculiar morphological features of the platypus intestinal mucosa raise questions concerning traditional concepts of intestinal gland formation as well as the origin and migration of intestinal epithelium with regard to this particular species.
Pathways of clearance in mouse lungs exposed to iron oxide aerosols
Authors: Sorokin Sergei P. , Brain Joseph D. 
Published: February 2005

AbstractThe history of particle clearance was studied in lungs of mice serially sacrificed at intervals up to 14 months following single exposures to an aerosol of submicronic, particulate, iron oxide used as a similitude for atmospheric dust. Clearance was followed by light microscopy in unstained and Prussian blue stained frozen and plastic embedded sections, as well as by electron microscopy, where iron oxide can be recognized by its form. Related problems were investigated through histochemical demonstration of acid phosphatase activity in pulmonary lysosomes and Prussian blue staining of various tissues after administration of iron compounds by gastrointestinal and vascular routes.The iron particles settle extensively but not uniformly on pulmonary alveolar surfaces. Clearance is centripetal and involves two mechanisms, an extracellular mechanism fed by fluid currents sweeping across the surface, and a cellular mechanism principally involving alveolar macrophages. In the early post exposure period both actively remove deposited particles predominantly through the pulmonary airways. By 24 hours uncleared residues have become ingested and clearance thereafter results mainly from cellular action. Macrophages enter bronchial passages where they sometimes continue to pursue normal activities. A chronic phase of clearance begins when deposited particles become sequestered in macrophages of pulmonary connective tissues. These cells are reached by several routes, not least by crossing the bronchial epithelium. Particle clearance from these macrophages is very slow, and residue‐containing cells eventually congregate in lymphoid tissues surrounding major bronchi. These findings are discussed as they help to develop an overall picture of clearance from the lungs and as they bear on related topics, such as functional roles of alveolar and pulmonary connective tissue macrophages and the pathogenesis of chronic bronchial disease.
Adrenergic innervation of cat adrenal medulla
Authors: Prentice F. David , Wood Joe G. 
Published: February 2005

AbstractCat adrenal medulla was studied to determine whether or not an adrenergic nerve supply was available to medullary cells. The techniques used were those of routine electron microscopy, injection and uptake of “false” transmitter substance (5‐hydroxydopamine), injection of 6‐hydroxydopamine, which selectively destroys postganglionic adrenergic elements and a specific cytochemical method using glutaraldehyde and heavy metal techniques for cytochemical localization of biogenic amines. Each method consistently demonstrated adrenergic fibers and terminals in the adrenal medulla; these adrenergic elements contain dense, large core and small core vesicles which are not of the “dense cored” cholinergic type. Localization of adrenergic fibers and terminals is deemed significant since the latter had the bouton en passage configuration immediately adjacent to norepinephrine cells; adrenergic elements were not seen in close relationship to epinephrine cells. Consistency of the findings from the three techniques point to the fact that the norepinephrine cells of the adrenal medulla have a dual innervation, both cholinergic and adrenergic. This type of innervation pattern is not unique for the autonomic nervous system, but it has not been reported previously for adrenal medullary cells. It is believed that such an innervation pattern has functional and pharmacologic significance.
The fine structure of the myoneural junctions in the body wall muscles in Branchiobdella pentodonta whit. (Annelida, oligochaeta)
Authors: Farnesi Rosalba Maria , Vagnetti Daniela 
Published: February 2005

AbstractThe ultrastructure of the myoneural junctions in the body wall muscles has been studied in Branchiobdella pentodonta Whit. A single junctional type has been found. Within the terminal axon there are two types of vesicles, which differ in number, size and electron opacity. The junctional gap contains the basement membrane. The post‐junctional membrane displays concave patches on which slender projections arising from the outer lamina of the sarcolemma extend into the junctional gap. These concave patches overlie a cytoplasmic lamina made up of electron dense material.
A region of mitochondrial division in the epithelium of the small intestine of the rat
Authors: Jeynes B. J. , Altmann G. G. 
Published: February 2005

AbstractElectron microscopic examination of samples from various regions of the rat small intestine was carried out. The number of mitochondria in the epithelial cells was estimated. The counts were made in sections of cells cut along their longitudinal central plane. The errors involved in extrapolating these counts to the whole cells were also estimated.The average mitochondrial number per cell section was 21 in the lower third of the crypts, it gradually increased in the mid and upper thirds and reached about double, 42, at the villus base. The known forms of dividing mitochondria were identified in the mid and upper third of the crypts. The counts remained around 42 along the epithelium of the villi.Crypt cells are continually produced in the lower crypt; these cells migrate to the villi while differentiating into nonproliferative absorptive cells. After inhibiting mitosis by methotrexate, this migration continued (Altmann, 1974) and mitochondrial division persisted. In segments of the jejunum isolated surgically from the functional intestine for three weeks, mitosis and cell migration continued, but no evidence of mitochondrial duplication was found.Each mitochondrion probably undergoes a division as the crypt cells migrate from the mid‐crypts to the villus. As a result, the villus epithelial cells contain double numbers of mitochondria. It appears that the mitochondrial division is not directly related to mitosis and is elicited by a stimulus present only in the functional intestine.
The development of various generations of nephrons during postnatal ontogenesis in the rat
Authors: Goncharevskaya Olga A. , Dlouhá Helena 
Published: February 2005

AbstractThe structural development of individual nephrons has been investigated in the kidneys of young rats by microdissection.Superficial, intercortical and juxtamedullary nephrons in Wistar‐Konárovice rats aged 2 to 60 days have been followed. At two and five days of age the superficial nephrons were in an early stage of anatomical development. At this time intercortical and juxtamedullary nephrons were more developed, and basically resembled similar structures in adult animals with the exception that the loops of Henle did not have a thin ascending limb.At ten days of age all three types of nephrons were differentiated with the exception that the intercortical nephrons did not possess a thin ascending limb of Henle's loop.At selected stages of development there appears to be a direct relation between the length of the superficial nephrons and the weight of the kidney. Since individual segments of these nephrons do not grow at the same proportional rate, this relationship does not hold when compared to kidney weight.
Characteristics of bovine lung as observed by scanning electron microscopy
Authors: Mariassy A. T. , Plopper C. G. , Dungworth D. L. 
Published: February 2005

AbstractThe surface characteristics of the intrapulmonary airways and alveoli of the lungs from 12 young adult cattle examined by the scanning electron microscope are described. When compared with similar studies of the lungs of various other mammalian species, the bovine lung gneerally resmebles that of other mammals except for several important features: (1) Alveolar pores of Kohn are small and extremely rare; (2) Alveolar macrophages are seldom seen in alveolar air spaces; (3) Interlobular septa completely separate the lung into distinct lobules.
An unusual modification of endoplasmic reticulum in epithelial cells of the mouse ascending colon
Authors: Michaels John E. 
Published: February 2005

AbstractA rarely occurring structure that is apparently a modification of endoplasmic reticulum was observed in the epithelial cells of the ascending colon of the mouse. The structure consists of a stack of 3 to 15 parallel cisterna‐like elements separated by about 67 nm. The stacked cisternae usually are located adjacent to the basal end of the nucleus or in the region between nucleus and basal cell membrane. Top and bottom cisternae of many of the stacks have patent lumens and their outer membranes are lined by ribosomes. Most frequently, middle cisternae have attenuated lumens in their central regions. In some instances the width of the cisternal lumens is similar throughout. Closely apposed pairs of cisternae also occur. Some stacks have a concentric configuration. The intercisternal space contains tightly packed vesicles (38 nm) arranged in a hexagonal array. Many of the vesicles are connected to the membranes of the cisternae by stalk‐like projections. The vesicles also occur between the nuclear envelope and the adjacent parallel cistenae. Mitochondria are situated close to each stack.