bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of embryonic overgrowth on the avian optic tectum
Authors: Wilson Doris Burda 
Published: February 2005

AbstractThe effects of embryonic overgrowth on the avian optic tectum were determined during late developmental stages in 121 chick embryos in which overgrowth was induced surgically. The embryos ranged in incubation age from seven days through 21 days and showed a variety of gross brain defects, including fused optic lobes, fusion of one or both optic lobes with a cerebral hemisphere or with the cerebellum, absence or reduction of one optic lobe, convolutions of the tectal wall, and hydrocephalus. At seven days to 11 days of incubation, histological defects of the tectum included irregularities in the migration patterns of neuroblasts and abnormal stratification among the migrated neuroblasts. The most severe defects in the 12‐day through 21‐day tectum were in the stratification of the outer region which corresponds to the adult stratum griseum and fibrosum superficiale, whereas deeper areas of the tectum underwent relatively normal histodifferentiation. Epithelial rosettes were common until the sixteenth day, after which they disappeared almost entirely except for a few occasional ones near the ventricular zone. Preliminary behavioral observations of the defective embryos revealed random motility similar to that in the control embryos, but a failure to achieve the proper hatching position. Of 61 operated embryos maintained until hatching, only one was capable of emerging from the shell.
Fine structure of the atrioventricular node as viewed in serial sections
Authors: Thaemert J. C. 
Published: February 2005

AbstractAtrioventricular nodal tissue obtained from a two‐week‐old mouse heart was fixed in osmium tetroxide, embedded in Epon 812, and serially sectioned for electron microscopy. From the study of electron micrographic montages of the first 620 serial sections of the posterior‐inferior (tail) portion of the node, it was determined that many of the nodal cells are spindle‐shaped and each has a single, centrally‐placed, ellipsoidal nucleus. Other cells exhibit irregular surfaces with protrusions of variable dimensions and some are flattened. Most of the flattened cells are located in the peripheral borders of the posterior and lateral portions; irregularly‐shaped cells occupy deeper positions in the tail of the node. Two cells, which are different from all others, reside in the peripheral border of the medial portion. They are contiguous with one another and globular in shape, each containing a single, centrally‐placed, spherical nucleus. These two cells are sparsely endowed with myofilaments but contain many mitochondria. They may be pacemaker cells. Intercellular relationships among nodal cells exhibit a wide variety of complicated contact areas in addition to some rather simple contiguities of the lateral aspects of adjacent cells. No typical intercalated discs are present; however, junctional specializations between interdigitating protrusions of contiguous nodal cells do occur. Intimate contact between vesiculated nerve processes and nodal cells varies in extent from a profuse innervation in the posterior and lateral portions of the tail of the node to lack of contact with many of the cells in the medial and anterior portions. This pattern of innervation, in conjunction with the absence of maculae occludentes between cells of the posterior and lateral portions of the tail of the node but present between cells of the other portions, suggests that the medial and anterior areas are conductive and the posterior and lateral areas are regulative.
Blood supply of the human fetal mandible
Authors: Hamparian Arthur M. 
Published: February 2005

AbstractGross anatomic and radiologic studies of the blood supply to the human mandible of the full‐term fetus and newborn infant were performed on 22 specimens ranging from 320–538 mm crown‐heel length and 1,192–4,108 gm in weight. Ten specimens were injected with red‐lead and liquid soap to demonstrate the arteries radiographically. Twelve other specimens were injected with Castolite with a sprinkling of red‐lead and yellow dye. The best side of each specimen was studied by radiography and dissection. This study demonstrated: (1) a masseteric arterial plexus supplying the coronoid process and the lateral wall of the ramus with contributions from the facial, masseter, transverse facial and external carotid arteries or combinations thereof; (2) a mental arterial plexus anastomosing with the mental, submental and inferior labial arteries; (3) an inferior alveolar artery supplying most of the body of the mandible with a majority of its branches passing in an upward direction; and (4) periosteal vessels supplying the lower border of the mandible and receiving their blood supply from the blood vessels supplying the muscles attaching to these areas and the periosteum. Supplemental to the above findings were anastomoses between the submental, mylohyoid and sublingual arteries along the medial border of the mandible. Also a significant variation not previously recorded was noted in one specimen in which the sublingual artery originated from the facial artery rather than the lingual.
Lobular structure of hemochorial primate placentas, and its relation to maternal vessels
Authors: Gruenwald Peter 
Published: February 2005

AbstractStructure of the placental lobule and its topographic relation to the ostia of maternal vessels were studied in primates with hemochorial placentas. The lobule contains most of the terminal villi, whereas stems predominate in interlobular areas. The placenta of Tarsiidae consists of one lobule supplied by one maternal artery. Ceboidea (New World Monkeys) have multilobular placentas. In both forms arteries reach the intervillous space below the center of a lobule, and then continue into the lobule as perforated, branched channels which lose their maternal vessel wall. In Cercopithecoidea (Old World Monkeys) each maternal artery has a convolution in the decidua below an interlobular area, then continues straight to a point below the center of a lobule, and opens there. Hominoid (ape and human) placentas are supplied by much larger numbers of arterial convolutions at interlobular areas, with interlobular openings close to anchoring points of villous stems. Venous drainage is at the periphery in Tarsius and interlobular in all other forms. The interlobular intervillous space may have more or less specialized portions emptying into maternal veins. Circulation in the intervillous space must be directed from the center toward the periphery of the lobule in Tarsiidae and Ceboidea. In Cercopithecoidea and Hominoidea the path of maternal blood issuing from arteries is not known. It is suggested that arterial blood irrigates first the periphery, and that this is the cause of dense proliferation of villi there.
The relationship between jaw, arm and leg size in three ethnic groups
Authors: Lavelle Christopher L. B. 
Published: February 2005

AbstractOverall height, arm length, leg length and mandibular size were measured in 800 male subjects from three ethnic groups aged three months to 20 years. Mandibular size or limb size showed a linear relationship when plotted against overall body height for each ethnic group and emphasized that different relationships exist between the size of a region and that of the body as a whole in caucasoids, negroids and mongoloids.
Distribution of sacral afferent axons in cat urinary bladder
Authors: Uemura Etsuro , Fletcher Thomas F. , Dirks Victor A. , Bradley William E. 
Published: February 2005

AbstractTerminal axon density was examined in five selected regions of the urinary bladder in five cats. The trigone region had more terminal axons than other bladder regions. Extra‐terminal axons in the trigone were outside muscle fascicles and thought to be afferent axons related to the hypogastric nerve.In four of the cats, afferent axons of the pelvic nerve were identified by degeneration following sacral spinal ganglionectomy. The afferent axons were distributed equally to all regions of the bladder, implying that micturition sensitivity is not preferentially organized in the bladder. One‐third of the sacral afferent axons crossed to the contralateral side of the bladder. This bilateral redundancy constitutes a safety feature. Afferent terminal axons were more numerous outside than inside muscle fascicles. Morphologically, afferent terminations outside muscle fascicles appeared to be tension receptors, while terminations inside the fascicles are candidates for volume receptors. The greatest number of degenerating terminal axons was found 14 days after ganglionectomy. Thirteen percent of degenerating axons contained agranular vesicles, and these were presumed to be autonomic postganglionic neurons with cell bodies in spinal ganglia.
Heart development in the mexican salamander, Ambystoma mexicanum. II. Ultrastructure
Authors: Lemanski Larry F. 
Published: February 2005

AbstractHeart development in the Mexican axolotl, Ambystoma mexicanum, from early embryonic stages to the adult was studied by electron microscopy. During early development, myocardial cells exhibit scanty cytoplasmic matrixes which contain numerous large yolk platelets and lipid droplets. As development progresses the yolk and lipid materials become reduced; the cytoplasmic matrixes increase in glycogen content and membranous organelles. Degradation of yolk platelets appears to take place by an “unraveling” process. The Golgi complex becomes well‐developed just prior to the first heart beats and its many associated vesicles are suggestive of secretory activity. Degeneration and death of certain myocardial cells are evident at the onset of trabeculation. Several mechanisms for myofibrillogenesis appear to operate both simultaneously and at different developmental stages. Pre‐heart‐beat myocardial cells display ribosome‐containing amorphous masses and unorganized 60 Å and 140 Å filaments in their cytoplasm. They also have electron‐opaque plaques on their plasma membranes. Sarcomeric myofibrils first appear parallel to and immediately beneath the sarcolemma. This occurs at stage 34, the heart‐beat initiation stage (6 days). During later development “isolated” Z band‐myofilament complexes, numerous loosely‐organized 60 Å filaments and a few 140 Å filaments are observable in the cell matrixes. This suggests that Z bands may form centers for myofibril organization at these stages. Also at later stages, polysomes are parallel to the already‐formed myofibrils. These polysomes are possibly synthesizing contractile proteins “in situ” and may represent a mechanism for myofibril diameter growth. In late embryonic and juvenile stages 100 Å—110 Å filaments appear to be continuous between Z bands of adjacent myofibrils. It is possible that such filaments of intermediate size are involved in aligning myofibrils into register during advanced developmental stages.
The relationship of organ weight, body weight and age in mice
Authors: Simpson L. O. , Spears G. F. 
Published: February 2005

AbstractA method is described which permits the examination of the influences of increasing age and body weight on organ weights. Polynomial multivariate analysis is performed by computer, and the predicted organ weight values permit the construction of three dimensional graphs which show the influence on organ weight of all combinations of age and body weight. The application of the method will allow the physical biology of organisms to be determined with considerable precision over their life span.
Cytological aspects of pineal development in rats and hamsters
Authors: Clabough Jeanne W. 
Published: February 2005

AbstractEvidence has been accumulating which supports the hypothesis that through phylogenetic evolution, the mammalian pinealocyte has evolved from the pineal photoreceptor‐cell which is characteristic of certain lower vertebrates. In the present study, developing pineal glands in fetal rats and hamsters were studied at light and electron microscopic levels to determine whether or not the ontogenetic development of pineal cells affords clues to their phylogenetic origin. Pineal development in fetal rats occurs during the last eight days of gestation (14–22) and in fetal hamsters, during the last five days of gestation (11–16). The pineal gland exhibits many similarities in the two species as it develops from a tubular evagination of the diencephalic roof into a compact cellular mass. Different cellular types could not be readily distinguished in fetal material from either species. In both animals, as long as lumina persist, cells bordering on these lumina exhibit surface modifications reminiscent of developing photoreceptor‐cells, i.e., an “ellipsoid‐like” apical cytoplasmic bulge which often contains one or two centrioles and bears a ciliary derivative exhibiting a 9 + 0 tubular configuration. As pineal tissue proliferates, the lumina and cilium‐like structures disappear. The findings, when considered with phylogenetic studies, strengthen the hypothesis that the mammalian pineal gland contains cells derived from the photoreceptor‐cell line.
The postnatal development of the respiratory system of the opossum. I. Light and scanning electron microscopy
Authors: Krause William J. , Leeson C. Roland 
Published: February 2005

AbstractThe postnatal development of the respiratory system in the opossum has been traced, using 102 specimens divided into 11 groups according to snout‐rump length. At birth, the lung is markedly underdeveloped and is represented by a pumitive system of branching airways that end in a number of terminal chambers or sacs. The airways, constituting the conducting portion of the lung, are lined by columnar epithelium that is devoid of cilia and goblet cells. The terminal air chambers contain an extensive capillary bed and are surfaced by squamous epithelium interspersed with scattered cuboidal cells. By the 3 cm stage, bands of smooth muscle have differentiated in relation to the bronchial epithelium and scattered cilia are present in the epithelium of the trachea and bronchi. Air chambers immediately adjecent to established bronchi differentiate further and become incorporated into the bronchial tree and new air chambers develop at the most distal extent of the bronchial system up to the 15.5 cm stage. Numerous spaces lined by squamous epithelium, which represent the first appearance of the arbor alveolaris, appear within the cellular stroma of the lung of the 7 cm opossum. By the 20 cm (juvenile) stage, mature alveoli, containing many vacuolated cells, are present and a thick collagenous lamina has developed between the pleura and the lung parenchyma.
The ultrastructure of adrenergic neurons in sympathetic ganglia of the newborn rabbit after treatment with 6‐hydroxydopamine
Authors: Papka Raymond E. 
Published: February 2005

AbstractThe effects of 6‐hydroxydopamine, an analog of dopamine which produces degeneration of peripheral adrenergic nerve terminals in adult animals, on adrenergic neurons in the sympathetic ganglia of newborn rabbits were studied with the electron microscope. Animals were treated with a 50 mg/kg dose of 6‐hydroxydopamine within six hours after birth and subsequently given daily doses until seven injections had been administered. The results of this study indicate that the adrenergic neurons underwent a “reaction” to 6‐hydroxydopamine which was first manifested by an increase in filaments and smooth membranous structures in the cell bodies. In the axons of these neurons a similar increase in filaments and membranous elements, as well as accumulations of dark‐core vesicles and mitchondria, were evident. Microtubules, although plentiful in normal cells and axons, were not conspicuous in these cells and axons. This initial reaction was later followed by degeneration of the cell bodies and axons and their eventual disappearance, leading to a reduction in cell population and size of the ganglia. It is suggested that the initial effect of 6‐hydroxydopamine on adrenergic neurons (in newborn animals) may be an interference with their axoplasmic transport mechanism which leads to cell degeneration and death. This study also has shown that some of the small “granule‐containing” cells in sympathetic ganglia may be sensitive to 6‐hydroxydopamine, at least in newborn rabbits, as is indicated by their degeneration.
Intestinal absorption of ferritin in the suckling rat
Authors: Shervey Paul D. , Gardner Paul J. 
Published: February 2005

AbstractExtensive absorption of ferritin was demonstrated in the proximal and distal ileum of 8–12 day‐old rats. In some regions, ferritin droplets were distributed in the basal cytoplasm of the columnar epithelium and in the lamina propria one hour after feeding. Subsequently, iron‐positive material was localized adjacent to vessels of the lamina propria and in macrophages. Absorption of lesser quantities was demonstrated in the duodenum.
Location of nerve cells producing the synaptic vesicles situated in the substantia gelatinosa of the spinal cord (1)
Authors: Duncan Donald , Morales Ricardo 
Published: February 2005

AbstractA search for the cells of origin of synaptic vesicles with electron‐opaque cores and located in the substantia gelatinosa was attempted by subjecting cats to transection of dorsal roots and double hemisection in the upper lumbar region. The hemisections were accompanied by interruption of the dorsal rootlets to the affected segment. The cats were perfused with buffered aldehydes and processed for electron microscopy 55–71 days after the operations. Comparison of intact and operated sides of the rhizotomized cats revealed no discernible differences in numbers and location of the granulated vesicles associated with the substantia gelatinosa. In cats with double hemi‐section plus rhizotomy the distribution of the granules was the same on the normal and operated sides but the numbers appeared to be reduced especially close to the surgical incisions. Dark‐core vesicles were situated in association with the Golgi apparatus of substantia gelatinosa neurons, in dendrites, in small axons and in synaptic sacs in all material studied. It was concluded that most of the granulated vesicles located in the substantia gelatinosa are produced by small neurons in the immediate vicinity of their axon terminals.
Radioimmunological evidence for early functional activity in chick embryonic beta cells
Authors: Green Tim D. , Benzo Camillo A. 
Published: February 2005

AbstractA radioimmunoassay for insulin was utilized to investigate developmental aspects of insulin storage and secretion in the chick embryo. Immunoreactive insulin was detected in both the pancreas and blood plasma from the fifth embryonic day onwards. The present data show that the chick embryonic beta cell has the potential for activity early in development, and that insulin may be secreted at earlier developmental stages than hitherto accepted.
Fine structural studies of the sino‐auricular nodal tissue in the heart of a teleost fish, misgurnus, with particular reference to the cardiac internuncial cell
Authors: Yamauchi Akio , Fujimaki Yoko , Yokota Reiko 
Published: February 2005

AbstractThe sino‐auricular nodal tissue of the heart of the loach (Misgurnus anguillicaudatus, Cantor) contains (1) myocardial cells receiving rich innervation, (2) isolated nerve cells, and (3) cardiac internuncial cells which are interposed between autonomic axon terminals and myocardial cells. Structural specializations are noted at the synapse between the autonomic axon and the myocardial cell, as well as at the axon‐internuncial cell synapse. Between the internuncial cell and the myocardial cell, attachment plaques are present with a patchy locus of a close junction, wherein the extracellular space appears to be almost obliterated. Estimations were made of the surface areas of an internuncial cell body and a nerve cell body as revealed by serial sampling of the tissue at about 0.5 μ intervals. The results show that for an internuncial cell body followed over a length of 15 μ, 52.5% of its total surface is covered by vesiculated axons, 3.8% by non‐vesiculated axons, 12.2% by myocardial cells, and 3.1% by Schwann cell processes; for a nerve cell body followed over a length of 16 μ, only 1.8% is covered by vesiculated axons, 0.5% by non‐vesiculated axons, nil by myocardial cells, and 96.4% by a satellite cell and its processes. It is considered that the internuncial cell represents a specialized cell type in the nodal tissue of the fish heart, playing a role in modulating the autonomic nerve impulses before they are transmitted to the effector myocardial cells.
Large inclusions in receptor cells of the amphibian lateral line
Authors: Wickham M. Gary 
Published: February 2005

AbstractWith few exceptions, anatomical studies of amphibian lateral line systems have been limited to gross and light microscopic investigations. The lateral line of Xenopus laevis had been studied at the fine structural level, but electron microscopic data are available only for late larval and adult stages. A comparison of the ultrastructure of lateral line receptor cells at different stages in the life histories of urodele species indicates that four categories of large (to 3 μ diameter) organelles occur in these animals. Apical and synaptic dense bodies are morphologically similar but lie at opposite ends of the cell. Lysosomes and multivesicular bodies are concentrated in regions of the Golgi apparatus. Previously undescribed perinuclear crystalline inclusions seem to be associated with bundles of microfilaments. Inclusions of similar internal structure also occur within the nucleus. The location of a crystalline structure in the nucleus makes the definition of a more typical nucleolus mandatory.
Emiocytosis of B granules from saurian pancreatic islets perifused in vitro
Authors: Rhoten William B. 
Published: February 2005

AbstractSplenic islets of Anolis carolinensis incubated in an in vitro perifusion system with media containing a non‐stimulatory concentration of glucose had the same ultrastructural appearance as islets removed from an intact animal. When horseradish peroxidase was included in this medium, no profiles suggestive of emiocytotic release of B granules were observed despite basal insulin secretion.With cytochalasin B and a high concentration of glucose, the B cells exhibited margination of their secretory granules and moderate degranulation, but rarely were profiles suggestive of emiocytosis seen. In the presence of cytochalasin B, glucose and the other insulin secretagogues used, the B cells were more degranulated than with only cytochalasin B and glucose present, but profiles indicative of emiocytosis were infrequently encountered. Emiocytosis of the B granules was demostrated convincingly with the inclusion of peroxidase and the above agents. Virtually all the B cells had at least one secretory granule fused with the limiting membrane and surrounded by the peroxidase, and some B cells exhibited multiple release of granules. From these observations it is concluded that emiocytosis plays a major role in the secretion of insulin from B cells of Anolis.The B cells from control perifusions, as well as from intact animals, did not contain a microfilamentous cell web. Granular or filamentous masses were not demonstrated in B cells from splenic islets perifused with cytochalasin B. The mechanism of emiocytotic release of insulin from the B cells of Anolis is discussed with reference to these observations.
Uptake of marker particles by in vitro ventilated and perfused rat lung
Authors: Vidić Branislav 
Published: February 2005

AbstractColloidal gold marker was present in the capillary lumen and at various stages of pinocytosis and passage through the endothelial cells. It was occasionally located in the peri‐endothelial space, close to the basement membrane. The uptake of marker by other cells was not observed. These results suggest the existence of two barriers, the biological (pinocytotic and hydrolytic capacities of the endothelial cells) and mechanical (permeability of the basement membrane).