bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution of nerves in human primary teeth
Authors: Rapp Robert , Avery James K. , Strachan Donald S. 
Published: February 2005

AbstractHuman primary teeth in the stages of late root formation, root completion and root resorption were impregnated with silver to allow study of the distribution of nerves in the pulp.Neural trunks composed of many individual, myelinated nerve fibers enter the apical foramen of primary teeth and pass in a coronal direction, often in close association with blood vessels. Neural trunks in the crowns of the teeth divide into smaller branches, which divide further into myelinated nerve fibers, which become interwoven to form the parietal layer (plexus of Raschkow). An occasional unmyelinated fiber leaves this zone and passes into the odontoblastic layer of cells where it appears to terminate with no specialized ending apparent. No nerves were seen to enter the predentin or dentin.As primary teeth begin to undergo root resorption, degenerative changes such as thickenings, varicosities and fragmentation appear in the nerves. The quantity of neural tissue also decreases. The greater the amount of resorption, the greater are the degenerative changes. In teeth in which the roots are almost completely resorbed, only a small number of nerves remain.The pattern of distribution of nerves in primary teeth is observed to be similar to that of permanent teeth. The density of the innervation of the primary teeth, however, is not found to be as great as that of permanent teeth.
A technique of decalcification suited to electron microscopy of tissues closely associated with bone
Authors: Baird Irwin L. , Winborn William B. , Bockman Dale E. 
Published: February 2005

AbstractSystematic experiments have resulted in a method of decalcification which, although specifically developed for cytological study of reptilian aural tissue, should be applicable to other problems involving electron microscopy of organic components of bone or tissues closely associated with bone. Reptilian otic capsules and control specimens of mammalian hepatic tissue were subjected to planned variations of fixatives and decalcifying agents, embedded, sectioned, and evaluated by light and electron microscopy. Additionally, applicability of the more satisfactory agents to other mammalian tissue was checked by limited testing on specimens from Mongolian gerbils. Acceptable results were achieved in tissues fixed in glutaraldehyde, and then decalcified in cold 0.1 M solutions of disodium or tetrasodium EDTA (adjusted to pH 7.2–7.4 with sodium hydroxide or versenic acid, respectively), containing 4.0% glutaraldehyde; following decalcification, specimens were washed in buffer, postfixed in osmium tetroxide, and embedded in epoxy resins with minor modification of standard techniques. Acceptable cytological detail and morphological relationships were retained, and extended treatment with the decalcifying solution did not apparently result in degradation of tissues.
A study of the interosseous distance between the radius and ulna during rotation of the forearm
Authors: Christensen John B. , Adams John P. , Cho K. O. , Miller Lawrence 
Published: February 2005

AbstractA roentgenological and gross anatomical study of the variation in the interosseous distance between the radius and ulna during the rotation of the forearm was made on cadavers. It was found that the neutral position provides the widest interosseous distance at different levels of the forearm compared with all other supinatory and pronatory positions. The average of the interosseous distances is greatest at the junction of distal and middle thirds of the radius, except in pronation 90°.Our observations show that the magnitude of the interosseous distance is largely proportional to the radius and ulna being in the same plane in a particular position of rotation of the forearm. In the neutral and supinatory positions, the point of the widest interosseous distance occurs more frequently in the middle third of the forearm, and in pronatory positions, in the distal third. Observations were also made on ligamentous specimens for the variation of tension of the interosseous membrane and of various planes occupied by the radius and ulna at different positions of rotation. The interosseous membrane was found to be taut in the neutral position in its major portion but lax in both pronation and supination.
The localization of mitotic figures in regenerating mouse liver
Authors: Melvin Joan B. 
Published: February 2005

AbstractThe number of mitotic figures present at one time in regenerating mouse liver, 48 hours after injury with CCI4, was increased by administration of colchicine. The livers were injected with india ink at the time of sacrifice to outline the blood vessels, and histological sections were made. Microscopic examination supported by statistical studies indicated that mitotic figures do not occur at random at this time in regenerating mouse liver. The dividing cells were found in close proximity to the terminal twigs of the branch of the portal vein in zone one of the functional lobule described by Rappaport.
Cell migrations to the isocortex in the rat
Authors: Hicks Samuel P. , D'Amato Constance J. 
Published: February 2005

AbstractCells that took up tritiated thymidine (H‐3T) at various periods of intrauterine and early infant life in the periventricular proliferative zone and migrated to form the isocortex in the rat were tracked autoradiographically in series of stages to characterize their movements. Cells labeled at any stage soon separated themselves into cohorts, some continuing to proliferate, others migrating at once, and still others delaying before migrating. Migratory cells moved to the developing cortex along the curved and oblique paths of the pallial fibers, whose basic plan was established by the early thalamocortical fibers. Magnitude of speed was 15 to 30 μ per hour. The primitive neural cells that originated on each of the fourteenth to eighteenth intrauterine days first reached the cortex in about 48 hours, others took two or three days longer. Migrations originating on the nineteenth to twenty‐first days continued into the week after birth; as the primitive cells approached the cortex, however, they differentiated into young neurons, and traveled perpendicularly to its outer part. The first cohort of twentieth day labeled cells reached their intracortical destinations in about three days, the last in about ten days. The isocortex was formed essentially from within outward. The first neuroglia destined for the isocortex arose on the twenty‐first intrauterine day.
On the presence of peripheral‐like nervous and connective tissue within irradiated spinal cord
Authors: Gilmore Shirley Ann , Duncan Donald 
Published: February 2005

AbstractCells with elongated nuclei resembling those of fibroblasts and/or Schwann cells had been noted previously in x‐irradiated portions of rat spinal cords. The present experiment was undertaken to determine the identity and fates of these cells. For this experiment, a 5 mm length of lumbosacral spinal cord was irradiated (4000 R) in three‐day‐old Holtzman rats. Groups of these rats and their litter mate controls were killed at intervals from 11 through 60 days following irradiation. Most of the spinal cords were prepared for light microscopic examination; a few were prepared for ultrastructural studies. Light microscopic examination revealed that the cells in question became observable near the dorsal roots within and immediately caudal to the irradiated area in a few rats as early as 15 days post‐irradiation and in all rats by 19 days following irradiation. The number of cells increased rapidly and in some cases filled the dorsal funiculi. Axons that were intermingled with these cells usually became myelinated approximately 25 days post‐irradiation. The myelin that formed on these axons resembled peripheral rather than central myelin. Reticular fibers were also abundant in the cell aggregations. The ultrastructural studies confirmed these observations. The data indicate that these cells were involved in formation of peripheral‐like nervous tissue within the spinal cord of all irradiated rats.
Electromyography and cinematography of leg and foot (“normal” and flat) during walking
Authors: Gray Edwin G. , Basmajian John V. 
Published: February 2005

AbstractElectromyography with fine‐wire electrodes and special equipment for synchronized motion pictures were used to study six muscles of the leg and foot during walking in five different ways in ten “normal” and ten flatfooted subjects. Detailed analyses and comparisons of the two groups are described and discussed.Tibialis Anterior has two peaks of activity at heel‐strike and toe‐off of the stance phase; is inactive during mid‐swing and middle of the stance phase; is active at full‐foot in flatfooted subjects, and generally more active during toe‐out and toe‐in walking. Tibialis posterior is inactive through the swing phase. In flatfooted persons it becomes activated at heel‐strike and more active at full‐foot during level walking. The toe‐out position reduces its activity. Flexor hallucis longus is most active in mid‐stance; during toe‐out walking, activity increases in both phases, generally being more active in “normal” persons. Peroneus longus is most active at mid‐stance and heel‐off and generally more active in flatfooted persons. Abductor hallucis and Flexor digitorum brevis are generally more active in flatfooted persons. An important regular pattern of inversion and eversion during the walking cycle is described. Contingent arch support by muscles rather than continuous support is the rule, muscles being recruited to compensate for lax ligaments and special stresses during the walking cycle.
The innervation of the joints of the foot
Authors: Gardner Ernest , Gray D. J. 
Published: February 2005

AbstractThe nerve supply of the ankle joint and of the joints of the foot was studied in dissections of fetal and adult feet and in serial sections of fetal feet stained with silver.The ankle joint was supplied by the tibial, sural, deep peroneal, and saphenous nerves, and by the accessory deep peroneal nerve when present.The tarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves, and on their dorsal aspects chiefly by the deep peroneal nerve. The joint between the lateral and intermediate cuneiform received branches from the intermediate dorsal cutaneous nerve also. The lateral dorsal cutaneous nerve and the accessory deep peroneal nerve when present provided additional branches to the subtalar and calcaneocuboid joints.The tarsometatarsal joints were supplied on their plantar aspects by the medial or lateral plantar nerves. Most of them were supplied on their dorsal aspects by the deep peroneal nerve, but the cuboid‐metatarsal joints received their supply from the intermediate dorsal cutaneous nerve. The intermetatarsal joints had a similar but sparser supply. The joint between the fourth and fifth metatarsal received branches from the intermediate dorsal cutaneous nerve.The plantar digital nerves provided the main supply to the metatarsophalangeal joints. The dorsal aspect of the first metatarsophalangeal joint was supplied by the deep peroneal and the medial dorsal cutaneous nerves, of the second metatarsophalangeal joint by the deep peroneal nerve, and of the fourth and fifth metatarsophalangeal joints by the lateral dorsal cutaneous nerve. The interphalangeal joints did not receive articular branches from the dorsal digital nerves, except in the case of the interphalangeal joint of the big toe, which was supplied by the deep peroneal and the medial dorsal cutaneous nerves.
Formation of the redundant nuclear envelope in monkey spermatids
Authors: Franklin Luther E. 
Published: February 2005

AbstractDevelopment of redundant nuclear envelope was observed in Erythrocebus patas and Macaca mulatta spermatids.As the acrosome forms around the anterior part of the nucleus, the underlying nuclear envelope becomes more dense in appearance. Changes which lead ultimately to formation of the redundant nuclear envelope of mature spermatozoa involve only the posterior region of the envelope which does not lie beneath the acrosome.The first recognized change is separation of the nuclear envelope from underlying chromatin by an intervening band of lightly stained nuclear material, around the posterior quarter of the nucleus. The separation increases and the bulged region of the nuclear envelope is drawn caudally as nuclear condensation progresses. The caudally extended region of the nucleus is comprised of nuclear material of low electron density and pores are present in the envelope of the extended areas.The chromatin aggregates in late spermatids becomes homogeneous in appearance when the nucleus flattens into a paddle shape. Nuclear protrusions are present at both posterior corners of the flattened nucleus at this stage of spermiogenesis but only one protrusion is well developed. Membrane remnants of the extended nuclear envelope remain in mature spermatozoa as the redundant nuclear envelope.
The compressive properties of single osteons
Authors: Ascenzi Antonio , Bonucci Ermanno 
Published: February 2005

AbstractThe compressive strength of single human osteons has been investigated in specially prepared samples using a microtesting machine equipped with a microwave micrometer. The main conclusions which can be drawn from our results are: (1) In agreement with Gebhardt's theories the ultimate compressive strength is greatest for osteons having transversally oriented fiber bundles, lowest for osteons having longitudinally oriented fiber bundles, and intermediate for osteons whose fiber bundles change direction in successive lamellae through an angle of about 90°. (2) The modulus of elasticity is greatest in osteons with transversally oriented fiber bundles. (3) With all three types of osteon the stress‐strain curves for fully calcified osteons are markedly different from those for osteons with low calcium content, the modulus of elasticity being much lower in osteons of the latter type. (4) Age seems to have no measurable influence on the compressive properties of osteons. (5) The comparison of compressive properties in single osteons and in macroscopic bone samples seems to support the view that the osteon is actually the mechanical unit of compact bone. (6) Fracture in osteon samples starts with microscopic fissures induced by shearing. (7) In every case these fissures form an angle of roughly 30°–35° with the axis of the osteon and do not appear to vary with the microscopic osteon structures. (8) Electron microscopy reveals distortion of bone crystals and breaking of collagen fibrils at the edges of the fissures.
The origin and survival of gastric parietal cells in the mouse
Authors: Ragins H. , Wincze F. , Liu S. M. , Dittbrenner M. 
Published: February 2005

AbstractUsing microradioautography, the origin of the gastric parietal (and zymogen) cells was deduced by observing the time of appearance of labelled parietal cells in relation to the other labelled cells in the gastric mucosa. In order to see whether the parietal cell divides in the adult mouse, time grain count curves of the labelled parietal cells were made from animals which were killed at 1–291 days after thymidine 3H injection DPT). Parietal cell survival was followed by observing the disappearance of the labelled parietal cell population. Parietal cells appear to be entirely derived from other cells since a significant number of labelled parietal cells does not appear unless the animal is allowed to survive for several days. Parietal cells do not appear unless the animal is allowed to survive for several days. Parietal cells do not seem to undergo mitosis in the adult mouse because the time grain count curves did not shift with time. Although a few labelled parietal cells persisted in the 291 DPT animals, a large majority of the labelled parietal cells disappeared by 90 DPT and had a half life of roughly 23 days. This suggests an element of renewal for the parietal cell population.
The fine structure of subsurface cisterns
Authors: Siegesmund K. A. 
Published: February 2005

AbstractStructures identified as subsurface cisterns (SSC's) have been observed in a variety of nerve cells from several different species. The SSC's occurred only in neurons and were most often opposite what appeared to be glial cells. Upon acrolein‐glutaraldehyde fixation, they appeared as distinct cytoplasmic organelles consisting of a short 0.5 μ long pentalaminate membrane in close parallel to the neuronal plasmalemma on one side, and parallel to an equally long segment of endoplasmic reticulum on the other side. A direct continuity was found between this segment of endoplasmic reticulum and the nuclear membrane, suggesting that a form of communication may exist between the neuronal nucleus and the subsurface cistern. Occasionally the segment of endoplasmic reticulum was missing and in its place a mitochondrion appeared which seemed to be in direct contact with the pentalaminate membrane.
The origin and the course of the communicating branch of the facial nerve to the lesser petrosal nerve in man
Authors: Vidić Branislav 
Published: February 2005

AbstractIn order to clarify the origin and the course of the communicating branch, 25 human nerve complexes (entire intra‐osseous part of the facial nerve, greater petrosal nerve, lesser petrosal nerve, communicating branch, auricular branch of the vagus) and stapedius muscles were dissected out and removed as a whole. Each of the 25 complexes was dehydrated, sectioned serially at 10–20 μ, and either stained with Luxol Fast Blue or treated with a silver technique. The communicating branch was observed to originate from the auricular branch of the vagus. It ascended first along the anterior side of the third intra‐osseous part of the facial nerve and then penetrated the stapedius. From within the stapedius some of its fibers continued anteriorly as a nerve bundle through the facial sheath of the second intra‐osseous part of the nerve. This nerve bundle separated from the seventh nerve upon approaching the geniculate ganglion, and joined the lesser petrosal nerve. The communicating branch consisted mainly of small myelinated fibers in the course of which either isolated ganglion cells or small ganglia were sometimes present.
The double nature of the intermediate dense line in peripheral nerve myelin
Authors: Revel Jean‐Paul , Hamilton David W. 
Published: February 2005

AbstractIn myelin of peripheral nerves it is shown that the intermediate dense line is split after aldehyde fixation (with uranium post‐treatment) with a 20 Å gap intervening between the apposed outer leaflets of the Schwann cell membrane. This gap is permeable to colloidal lanthanum, which indicates that it is continuous with the extracellular space. Our observations are discussed in light of data of other investigators.
Myofibrillogenesis and Z‐band differentiation
Authors: Kelly Douglas E. 
Published: February 2005

AbstractDeveloping myotubes in skeletal muscle tissue from the limbs of larval newts have been examined with respect to the ultrastructure and sequence of events accompanying myofibril formation. A population of filaments having a diameter of 100 Å is found to occur throughout and beyond the period of myofibrillogenesis. This population is in addition to developing actin and myosin filaments and probably does not contribute directly to myofibril formation. Rather it may represent a cytoskeletal network which ultimately becomes principally disposed around and at right angles to older myofibrils at the level of their Z‐bands.Assembly of thick and thin filaments into myofibrils seems to occur, in this muscle, predominantly near the periphery of the cell with registration of these components into A‐, I‐, and Z‐bands being accomplished as they assume progressively more internal locations. Z‐bands appear to develop by coalescence of Z‐bodies which in turn are earlier related to skeins of fine filamentous material which commonly occupy the most peripheral cytoplasm of these and other mesenchymally derived cells. Fine structural details of these skeins, Z‐bodies, and Z‐bands have been analyzed with regard to the several prevailing concepts of Z‐band architecture. An hypothetical sequence for myofibril formation and Z‐band differentiation is presented which takes into account several observations and relates them to the looping filament configuration previously proposed for mature Z‐band structure.
A comparison of alveolar macrophages and pulmonary surfactant(?) Obtained from the lungs of human smokers and nonsmokers by endobronchial lavage
Authors: Pratt Susan A. , Finley Theodore N. , Smith Morris H. , Ladman Aaron J. 
Published: February 2005

AbstractEndobronchial lavage was performed on eight smokers and eight nonsmokers. Centrifugation of lavage fluid produces a sediment consisting of two layers, a lower compact brown layer containing cells and an upper flocculent white layer. The brown layers from the smokers were greater in volume than those from the nonsmokers. Macrophages constituted about 93% of the cells from the smokers and about 63% of the cells from the nonsmokers. These data suggest that more free macrophages occur in the lungs of smokers than nonsmokers. In addition, many of the macrophages obtained from the smokers were filled with cytoplasmic inclusions. The volumes of white layers from the smokers were smaller than those from the non‐smokers. One white layer obtained from a nonsmoker was examined in a Wilhelmy balance and proved to be surface‐active. This may suggest that surface‐active material, pulmonary surfactant, is reduced in lavage fluids from smokers.
Fine structure of the resorptive cells in the teeth of frogs
Authors: Yaeger James A. , Kraucunas Eugenia 
Published: February 2005

AbstractTeeth undergoing resorption were dissected from the maxillae of frogs and prepared for electron microscopy using standard methods and methods designed to minimize demineralization. The resorptive cells overlapped one another, forming palisades. A central ruffled border was surrounded by a relatively structureless cytoplasmic “seal.” Crystals of mineral were present in the folds of the ruffled borders, and demineralized collagen fibrils were seen in the adjacent matrix in sections treated to prevent demineralization. The surfaces of the cells opposite the ruffled borders displayed numerous small villi.The cytoplasm of the resorptive cells contained a variety of lysosomes in various stages of development, mitochondria, scattered vesicles of endoplasmic reticulum and free ribosomes. Well developed Golgi zones were frequently seen, and occasional sections passed through centrioles. Two centrioles were commonly seen in such sections, but never more. Occasional patches of cytoplasm contained mitochondria and rough‐surfaced endoplasmic reticulum, resembling “blast” cell cytoplasm.We concluded that the resorptive cells of several mineralized tissues of various vertebrates are morphologically, indistinguishable.