bluuebunny/crossref_metadata_2025_split huggingface dataset:
Articular and internal remodeling in the human otic capsule
Authors: Gussen Ruth 
Published: February 2005

AbstractA comprehensive histologic study of the human otic capsule is presented demonstrating the interrelations between cartilage, bone, blood vessels and soft tissue throughout life. Remodeling occurs through continual degeneration of chondrocytes within the uncalcified articular surfaces of the stapediovestibular joint and through continual degeneration of cartilage about the cochlea and semicircular canals. Degenerated chondrocytes are removed by macrophages and new endochondral bone forms from adjacent osteogenically active blood vessels. The cartilage surfaces of the footplate and oval window are constantly replenished by new cartilage formed by mesenchymal cells of the annular ligament. Within the otic capsule, new cartilage forms from mesenchymal cells lining the labyrinth. Cartilage foci continually undergo partial replacement by endochondral bone with remnants of uncalcified cartilage matrix remaining, forming globuli ossei and interglobular spaces. In addition to continual endochondral bone formation partially replacing the continually forming and degenerating cartilage, chondroid bone forms by direct transformation of some cartilage to bone. These chondroid bone areas are cellular in young age groups, but become pale and relatively acellular with age. These processes occur throughout life, regardless of age or sex.
Formation and structure of the hemodichorial chorio‐allantoic placenta of the bat (Myotis lucifugus lucifugusy)
Authors: Enders Allen C. , Wimsatt William A. 
Published: February 2005

AbstractThe definitive chorio‐allantoic placenta of the bat is hemodichorial, since the cytotrophoblast layer persists to term. The syncytium contains intrasyncytial lacunae in which there is a continuous lamina interrupted only where portions of the syncytium communicate with the thin ectoplasmic layer at the surface of the maternal blood spaces.The future cytotrophoblast and syncytial trophoblast layers can be distinguished shortly after implantation. The future syncytial layer is not syncytial until after it invests most of the anastomotic vessels of the vascular tuft. The resulting labyrinth is converted from the vaso‐chorial to the hemodichorial condition as processes of syncytium pass through the basement membrane of the maternal vessels and spread out under the endothelial cells. The basement membrane is then included within the syncytium as the intrasyncytial lamina, and the maternal endothelial cells are lost. The numerous communications of the maternal vessels with the labyrinth seen early in gestation are reduced through occlusion of many of the efferent channels, which process also contributes areas of necrosis to the decidua basalis. The peculiarity of a maternal extracellular membrane being incorporated into the fetal portion of the placenta is discussed.
A comparative morphologic study of the cardiac innervation in domestic animals I. The canine
Authors: McKibben John Scott , Getty Robert 
Published: February 2005

AbstractCardiac nerves arising from the cervical and thoracic sympathetic chain, the vagi, and the recurrent laryngeal nerves of the dog were described. The findings are correlated with the nomenclature of the NA ('66) and proposals of the NAV ('67), and additional suggestions are made when appropriate. Although individual cardiac nerves were followed to specific areas of the heart, additional supplies to these areas were noted from the cardiac plexus. Sympathetic cardiac innervation arose primarily from the vertebral ganglion. Cranial vagal cardiac nerves on the left and caudal vagal cardiac nerves on the right contributed the majority of the parasympathetic cardiac innervation. Right cardiac nerves ramified primarily along the right coronary artery, left descending branch of the left coronary artery, circumflex branch of the left coronary artery on the left surface of the heart, and onto the right atrium. Left heart nerves, in addition to their direct contributions to all but the last area, proceeded along the circumflex branch of the left coronary artery on the caudal and right surfaces of the heart. Right nerves contributed more in the area of the S.A node, while left nerves formed a network in the area of the coronary sinus and A.V. node. Both sympathetic and parasympathetic nerves were followed to each area. It was noted that pulmonary innervation via the cardiac plexus would be disturbed by the technique of cardiac denervation referred to as regional neural ablations.
Nerve endings in the human endocardium
Authors: Johnston Brian D. 
Published: February 2005

AbstractThe endocardium of 12 human hearts was studied following methylene blue perfusion and immersion within eight hours after death. Photomicrographs presented show two major types of endings: complex unencapsulated endings, and end‐nets. Complex unencapsulated endings are discrete, much branched, highly variable “bush‐like” endings, which originate from myelinated fibers. These structures were found only in the atria, and particularly at atrio‐venous junctions. The close resemblance of complex unencapsulated endings to stretch receptors seen in other tissues suggests that they serve as “baroreceptors” in the heart. End‐nets are composed of repeatedly branching and anastomosing fine beaded fibers. The fine, beaded fibers originate from myelinated fibers, but the number and origin of the parent fibers is not known. In this study, end‐nets were found in the atria, on the atrioventricular valves, and in the ventricular endocardium. The function of the end‐net is unknown, and while most evidence suggests that it is sensory, motor function cannot be ruled out.
Central projections of spinal dorsal roots in the monkey. I. Cervical and upper thoracic dorsal roots
Authors: Shriver Joyce E. , Stein Bennett M. , Carpenter Malcolm B. 
Published: February 2005

AbstractA study of the central distribution of cervical and upper thoracic dorsal roots (DR) was made in 18 monkeys subjected to 31 dorsal rhizotomies. Degeneration was studied in multiple spinal and medullary sections stained by the Nauta technic.Dorsal roots C2 through T7 project fibers to: (1) portions of laminae III and IV, (2) the intermediomedial nucleus, and (3) portions of laminae VII, VIII and IX. DR C5 through T1 project fibers to medial parts of lamina VI. DR fibers reach cell groups of lamina IX via different trajectories, one of which is dominant in the brachial enlargement. Fibers project to the spinal accessory nucleus from C2 through C5 DR, while portions of the dorsal nucleus receive fibers from C5 to T7 DR.Ascending fibers in the fasciculus cuneatus: (1) arise from C1 through T7 DR, (2) exhibit only general segregation due to overlap, and (3) project somatotopically throughout the extent of the cuneate (CN) and accessory cuneate (ACN) nuclei. Fiber terminations in CN and ACN are: (1) similar for C1 through T1 DR, and (2) distinctive for T2 through T7 DR. The upper five cervical DR project fibers to: (1) the supraspinal nucleus, and (2) both the central cervical and intermediate nuclei. Cytological and degeneration studies suggest that the central cervical and intermediate nuclei constitute parts of the same cell column.
The uptake of ferritin by ileal absorptive cells in suckling rats. an electron microscope study
Authors: Graney Daniel O. 
Published: February 2005

AbstractAn electron microscopic study of the small intestine of rats from birth to 15 days of age has demonstrated a gradient of both structure and function along the length of the small intestine. During this period of development, only the ileum was found to absorb intact exogenous ferritin or colostral proteins. In newborn rats ferritin particles or milk proteins are incorporated by ileal absorptive cells into tubular invaginations of the apical plasmalemma which connect with vacuoles or cisternae in the apical cytoplasm. The ferritin particles are then transported by another vacuolar system to the supranuclear region where several such vacuoles coalesce to form a single supranuclear vacucle. After the first feeding the supranuclear vacuole is established in the ileal cells so that additional ingested proteins, whether ferritin or from milk, are transported from the cisternae directly to the supranuclear vacuole. There was no evidence in the present study to indicate that ferritin is transmitted from the ileal cell to the circulation. The subject of protein transport by the intestinal epithelium is reviewed briefly.
Morphological features of brown adipose cell maturation in vivo and in vitro
Authors: Dyer Robert F. 
Published: February 2005

AbstractThe maturation of brown adipose cells, derived at various time intervals from interscapular brown fat pads of neonatal rats, has been investigated electron microscopically. The major changes in in vivo brown adipose cells are related to lipid accumulation. In older animals, fat droplets are separated by a membrane complex, and membranous fragments are seen within large lipid inclusions. The ultrastructural characteristics of monolayer cultures of brown fat cells, isolated from neonatal brown fat pads by tryptic dissociation, and maintained for one to six days on a reconstituted collagen matrix, have also been investigated. Adipose cells in vitro are morphologically similar to control brown fat cells, and lipid accumulation closely parallels that seen in vivo. In vitro lipid droplet coalescence, impossible to visualize in vivo, has been documented by time‐lapse cinematography, and membrane complexes similar to those observed in vivo are seen. Major changes in cultivated fat cells, compared to in vivo cells, involve extensive glycogen deposition and breakdown of cytoplasmic ribosomal rosettes. Older cultures contain adipose cells exhibiting characteristics of white fat cells. Effects of tissue culture environment upon the brown fat cells, and the possible conversion of the brown fat cell into a white fat cell are discussed.
Studies on the fine structure of ovarian steroid‐secreting cells in the rabbit. I. The normal interstitial cells
Authors: Davies J. , Broadus Carole D. 
Published: February 2005

AbstractIn terms of their light microscopic appearance and fine structure the ovarian interstitial cells of the rabbit are typical steroid‐secreting cells. They are characterized by an abundance of agranular endoplasmic reticulum, spherical mitochondria with closely packed lamellar cristae, lipid droplets which appear to arise independently of the endoplasmic reticulum, conspicuous Golgi areas, a cytoplasm containing ribosomes and variable numbers of glycogen granules. A feature of the differentiation of the cells from the theca interna of atretic follicles or the stroma is the enlargement of the multiple Golgi areas and the progressive accumulation of agranular endoplasmic reticulum, possibly by “budding” from the Golgi cisternae. “Light” and “dark” cells are observed, the latter being characterized by a more closely packed agranular endoplasmic reticulum which tends to be tubular in type, that of the “light” cell being vesicular. Electron dense material (lipid?) is found in the vesicles and tubules of the agranular endoplasmic reticulum and in the Golgi cisternae; it may indicate a role of these structures in the biosynthesis of steroidal hormone. No fine structural changes specifically associated with pregnancy were observed. Degenerative changes are common and are described. The role of the interstitial cells, especially in relation to the production of 20 alpha‐hydroxyprogesterone, is discussed.
Sensory receptor organs of the human nasal respiratory mucosa
Authors: Cauna Nikolajs , Hinderer Kenneth H. , Wentges Robert T. 
Published: February 2005

AbstractHuman nasal respiratory mucosa has a limited capacity for localization of stimuli and discrimination of sensory modalities. In order to obtain morphological data on its receptor organs, histochmeical and electron microscopical studies were undertaken in six individuals ranging in age from 18 to 39 years.It was found that the nasal respiratory mucosa was supplied by non‐myelinated nerves which approached the mucosa in fascicles containing up to 200 axons. These fascicles were devoid of perineurial sheaths. They ramified repeatedly producing only one type of receptor organ — a simple terminal arborization. The finest terminal fascicles of the plexus ended either in the cell free zone of the lamina propria or in the spaces between the epithelial cells next to the basement membrane. The axons in the fascicles and in the endings were only partly insulated from one another by Schwann cell folds. The axoplasm of the terminal and preterminal nerve fibers contained accumulations of fine vesicles, simple granules and clusters of mitochondria. All nerve fibers gave a positive acetyl‐ and a negative butyro‐cholinesterase reaction.The plexiform endings of the nasal respiratory mucosa are different from any receptor organ of the adult human skin. They are reminiscent of the transitory, yet functional plexiform endings of the fetal skin which are found prior to the formation of the definitive receptor organs.
Electron microscopical studies on axonal degeneration in the rat iris following ganglionectomy
Authors: Roth C. D. , Richardson K. C. 
Published: February 2005

AbstractSuperior cervical ganglionectomy causes a very rapid and complete distintegration of adrenergic axons in the rat iris commencing less than 24 hours after operation. At 48 hours post‐operatively the electronmicroscopical appearance of the iris is normal with osmium tetroxide fixation because the debris has vanished and the abundant surviving cholinergic axons in the autonomic ground plexus give the impression that the total innervation is still intact. However, with permanganate fixation the denervated iris examined 48 hours to one year after operation lacks granular vesicles in its axons and appears in this single respect different from normal. After ciliary ganglionectomy the same kind of degeneration of individual axons begins within 24 hours, but continues for several days, involving a greater number of axons than the previous operation. Removal of both sets of ganglia intensifies the loss of axons and causes some atrophy of the iris tissues. A residue of apparently intact axons persists, however, for as long as ten months. The previously discordant results of ganglionectomy on iris innervation obtained by light microscopy are shown to be dependent on technical inadequacies, combined with the fact that in the earlier literature it was not known that there is a close intermingling of adrenergic and cholinergic axons in all parts of the iris plexuses.
Electron microscopic investigation of the source and direction of movement of lipid granules appearing in the hepatic perisinusoidal space following partial hepatectomy,
Authors: Parks Harold F. 
Published: February 2005

AbstractThe early sequelae of partial hepatectomy were studied at the ultrastructural level in livers of CFW mice that had been maintained on a normal diet or fed a fat‐free diet for four days prior to surgery. Normal‐diet animals showed a marked increase in number of small osmiophilic lipid granules in hepatocytes and the space of Disse during the first post‐operative hour and at all later intervals studied. This observation generally confirmed similar findings on C3H mice by Trotter ('65), but failed to provide conclusive indications of the source or direction of movement (i.e., from extracellular space into hepatocyte by engulfment, or from hepatocyte to extracellular space by secretion) of the granules in the space of Disse. In livers of fat‐free‐diet animals, where small lipid granules synthesized in the hepatocyte are recognizable by their osmiophobia (being derived from lipogenesis they are relatively highly saturated), synthesis and secretion by hepatocytes accounted for substantially all lipid granules appearing in the space of Disse during the first three postoperative hours and continued to occur during the fourth hour. This finding demonstrates the importance of the liver cell as a source of lipid granules (presumably very low density lipoproteins) appearing in the space of Disse after hepatectomy. Osmiophilic granules presumed to be of enteric origin, which were present in the space of Disse in very small numbers during the first post‐operative hours, increased in number during the fourth hour. The exact fate of these granules and their importance, if any, in the “post‐hepatectomy picture” could not be determined from available data.
Blood vessels and tissue space associated with the brain of the rat
Authors: Frederickson Richard G. , Low Frank N. 
Published: February 2005

AbstractTissues from adult Sprague‐Dawley rats fixed by perfusion with buffered aldehydes for a combined study of the vascular system of the brain are described in light and electron microscopy. In these preparations lack of shrinkage prevents the formation of perineuronal and perivascular spaces. However, connective tissue stains indicate restricted tissue space along the course of small arteries and veins. In fine structure this space is found within the walls of the vessels. It consists of a tubular extension of tissue space bounded inwardly by the endothelial boundary (basement) membrane and outwardly by the neural boundary membrane. Between these boundaries the formed elements of the media and the adventitia are found. The media consists of a thin layer of smooth muscle cells; each cells being enclosed in its own boundary membrane. The adventitia consists of cells and fibrous elements of the connective tissues which are derived, near the surface of the brain, from the intermingling of pial and vascular leptomeninges. This “neural” portion of the tissue space extends from the depths of the capillary bed (where it is obliterated by the fusion of boundary membranes), along the course of the blood vessels, through the subarachnoid space and into the general tissue space of the body.
Electron microscopical study of relaxation and constriction in frog arterioles
Authors: Phelps Patricia C. , Luft John H. 
Published: February 2005

AbstractMesenteric arterioles of frogs were selected under a dissecting microscope and compact vasoconstriction was induced by local application of a microdrop of epinephrine. Selected arterioles were fixed in situ at maximum constriction by flooding with buffered osmium tetroxide or glutaraldehyde. Fixation was faster than any vasoconstriction initiated by the onset of fixation. The arterioles were embedded in epoxy resin and regions of dilation and constriction were identified optically in the resin block. Ultrathin sections were cut at known levels for examination in the electron microscope. The localized constriction permitted the use of the relaxed, dilated region of the arteriole as a structural control for comparison against the fine structure of the constricted segment of the same arteriole. In constriction there was a dramatic change from the relaxed condition. The endothelial cells assumed a teardrop configuration and their nuclei protruded toward the lumen. The muscle cells and their nuclei became short and thick and demonstrated strongly indented borders, and the elastic membrane assumed a deeply pleated appearance. Both endothelium and smooth muscle cells appeared to adhere tightly to the elastic membrane for they faithfully replicated its convolutions. Bundles of thick (120 Å) and thin (70 Å) filaments were seen in the endothelial cytoplasm. The thick filaments were not contractile although the thin variety may shorten during vasoconstriction.
Ultrastructural and autoradiographic studies of mouse cleavage stages
Authors: Hillman Nina , Tasca Richard J. 
Published: February 2005

AbstractStudies of cleavage stage mouse embryos are reported, with particular emphasis upon nucleolar fine structural and functional changes. Multiple fibrillar primary nucleoli are present in the early 2‐cell embryo. In late 2‐cell embryos, some of these nucleoli acquire a peripheral zone of granules, while others reticulate, forming nucleoli composed of fibrillo‐granular cortices and fibrillar cores. The nucleoli of early 4‐cell embryos are composed only of fibrils. In the middle of the 4‐cell stage, some of the nucleoli acquire a peripheral granular zone, while others reticulate. The reticulated nucleoli of both the late 2‐cell and 4‐cell embryos can be considered, on the basis of their fine structure, to be definitive nucleoli. Early 8‐cell and morula embryos usually contain only two definitive nucleoli per nucleus. 3H‐5‐uridine‐pulsed embryos contain label localized in the nucleus, particularly over definitive nucleoli. Nucleolar labeling increases at each successive developmental stage. Beginning at the 8‐cell stage, re‐incubation in nonradioactive medium results in a significant decrease in nucleolar labeling and an increase in cytoplasmic labeling suggesting that more ribosomal RNA is transferred from the nucleus to the cytoplasm at the later cleavage stages.
An autoradiographic and morphological investigation of the postnatal development of the pineal body
Authors: Wallace Robert B. , Altman Joseph , Das Gopal D. 
Published: February 2005

AbstractCell proliferation in the pineal body of the hooded rat was studied with thymidine‐H3 autoradiography. Animals were either injected at birth and allowed to survive for variable periods or were injected at different ages and allowed to survive for a fixed period. Cell proliferation was high in the neonate (one and six hours of age) and continued at a decreasing rate into adulthood. The final development of the pineal body was believed to be due to cellular hyperplasia in the young animal and cellular hypertrophy in the adult. The morphological evaluation of the autoradiograms indicated that the principal proliferating components were parenchymal cells.
Metaplasia of cartilage into bone – a study by stain historadiography
Authors: Bohatirchuk F. P. 
Published: February 2005

AbstractDirect redifferentiation of cartilage into bone was studied during callus formation after experimental fractures in rats and rabbits, the combined techniques of histology and x‐rays (stain historadiography) being used. It was showed that in addition to the known osteoblastic bone formation a metaplastic type of bone formation also exists. In this process chondrocytes presumably redifferentiate into osteocytes.
Ultrastructural properties of primary olfactory neurons in fish (Lota lota L.)
Authors: Gemne Gösta , Døving Kjell B. 
Published: February 2005

AbstractQualitative and quantitative aspects of the normal fine morphology of the olfactory receptor cells. their cilia, axons, and neighboring cells, were investigated in the burbot. The receptor cells lacked olfactory tubercles and microvilli; they were isolated from each other by supporting and basal cells. The role of cilia and microvilli in chemoreception was discussed. Zonulae occludentes between the epithelial cells sealed off the interior of the olfactory mucosa of this fresh water animal from an environment with low osmotic activity. The number of receptor cells was estimated to be about 73 per 1,000 μ2. Glial cell processes penetrated from the connective tissue, investing small bundles of receptor axons within the epithelium. Formation of the filum olfactorium was described. The average number of axons in the central portion of the olfactory nerve was about 29 per μ2 in areas free of glial cells and connective tissue. The mean diameter of the axons in the nerve proper was 0.136 μ whereas a higher average was found beneath the epithelium. The presence of mitochondria imparted a considerable skewness to the distribution of diameters. The calculated total number of axons in the olfactory nerve corresponded with the number of receptor cells. The convergence of olfactory nerve fibers upon secondary neurons with myelinated axons was estimated to about 1,000:1.