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  • General Chemistry  (4,294)
  • Cell & Developmental Biology  (1,486)
  • 1975-1979  (5,780)
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  • 101
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 75-101 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The tesserate pattern of endoskeletal calcification has been investigated in jaws, gill arches, vertebral arches and fins of the sharks Carcharhinus menisorrah, Triaenodon obesus and Negaprion brevirostris by techniques of light and electron microscopy. Individual tesserae develop peripherally at the boundary between cartilage and perichondrium. An inner zone, the body, is composed of calcified cartilage containing viable chondrocytes separated by basophilic contour lines which have been called Liesegang waves or rings. The outer zone of tesserae, the cap, is composed of calcified tissue which appears to be produced by perichondrial fibroblasts more directly, i.e., without first differentiating as chondroblasts. Furthermore, the cap zone is penetrated by acidophilic Sharpey fibers of collagen. It is suggested that scleroblasts of the cap zone could be classified as osteoblasts. If so, the cap could be considered a thin veneer of bone atop the calcified cartilage of the body of a tessera. By scanning electron microscopy it was observed that outer and inner surfaces of tesserae differ in appearance. Calcospherites and hydroxyapatite crystals similar to those commonly seen on the surface of bone are present on the outer surface of the tessera adjacent to the perichondrium. On the inner surface adjoining hyaline cartilage, however, calcospherites of variable size are the predominant surface feature. Transmission electron microscopy shows calcification in close association with coarse collagen fibrils on the outer side of a tessera, but such fibrils are absent from the cartilaginous matrix along the under side of tesserae. Calcified cartilage as a tissue type in the endoskeleton of sharks is a primitive vertebrate characteristic. Calcification in the tesserate pattern occurring in modern Chondrichthyes may be derived from an ancestral pattern of a continuous bed of calcified cartilage underlying a layer of perichondral bone, as theorized by Ørvig (1951); or the tesserate pattern in these fish may itself be primitive.
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  • 102
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 103-119 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Classical light microscopic studies on pigmentation of Fundulus heteroclitus (killifish) indicated that there are three groups of light reflecting cells; one group on the surface of scales reflects white light, while two other deeper groups (the melaniridophores and the stratum argenteum) are iridescent. The results presented here show that: (1) The scale leucophores reflect white light by a Tyndall light-scattering mechanism, by virtue of the presence of randomly oriented organelles of “novel” morphology. (2) The iridophores of the melaniridophores contain stacks of irregularly-spaced, large reflecting platelets which function as an imperfect multiple thin layer interference system. (3) The stratum argenteum consists of a continuous layer(s) of iridophores with reflecting platelets which are so regularly packed as to approach an ideal multiple thin layer interference system. (4) In all three types of light reflecting cells, the dimensions and packing (orientation) of the reflecting organelles satisfactorily account for the chromogenic properties of the cells, including colors as viewed under transmitted, reflected, or polarized light. (5) The spacial relationships between these light reflecting cells and adjoining melanophores are different for each type of light reflecting cell. Furthermore, we propose to replace the term reflecting platelet with refractosome.
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  • 103
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 104
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 165-168 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A biomechanical model of the jaw mechanism in some reptiles is presented. Symmetrical muscle activity that produces equal forces on both sides of the head is assumed. The model predicts the position of the most posterior bite point and offers a functional explanation for this prediction. Turtles are used to illustrate the idea.
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  • 105
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 121-141 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study consists of a detailed cytoarchitectonic and Golgi analysis of a major tectofugal thalamic nucleus in the red-eared turtle, Pseudemys scripta elegans. Neurons in nucleus rotundus have a unimodal soma size distribution and a common dendritic branching pattern. They have long dendrites which undergo sparse, dichotomous branchings and contribute to dendritic fields that cover a third to half the dimensions of the nucleus. Spicules, 1-2 μ long, and complex appendages, 5-20 μ long, are found with low density on many dendrites in Golgi-Kopsch material. A few cells have beaded dendritic processes. Three cytoarchitectural regions can be differentiated in nucleus rotundus: a shell, a cell-poor region and a core. The shell is a monolayer of somata forming the peripheral boundary of most of the nucleus. The cell-poor region forms a thin zone concentric with and internal to the shell. Shell cells send some of their dendrites concentrically within this zone and others radially into the core region. Core neurons are dispersed within the neuropil of the nucleus and usually have spherical dendritic fields. However, peripheral core neurons have asymmetrical fields, so their dendrites do not extend beyond the shell. Caudomedial and central subregions of the core can be defined on the basis of neuronal density and cytology. Somata in the caudomedial area of the core are densely packed and have slightly darker staining cytoplasm than those in the central subregion. However, their dendrites are similar to those of the central core neurons. There is extensive dendritic overlap between the two subregions.
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  • 106
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 1-15 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fully mature adult Eisenia foetida sensory buds are abundant on the prostomium and the first segment. In subsequent segments they are restricted to the anterior half where they form a single row aligned with the setae and encircling the worm. In the more posterior regions of the worm the buds are widely separated and fewer. The surface of each bud is a raised circular or oval area from which 15 to 100 so-called sensory hairs arise, being cylindrical and apparently flexible. The number of these projections decreases toward the posterior end of the worm.In worms newly emerged from egg cocoons, the general pattern of distribution and external form of sensory buds resembles that of adults, but the buds are much fewer and smaller than in adults. Although these worms emerge with their definitive adult number of segments, new buds and additional sensory projections are formed during post hatching development.
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  • 107
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 195-207 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Serial coronal sections of the teeth and their surrounding tissues in the agamid lizard, Uromastix aegyptius, were examined with the light microscope in order to determine how these structures change as the teeth wear. Because new teeth are added only at the posterior end of the tooth row and older teeth are not replaced, the series of sections included the youngest as well as the oldest teeth. Two types of changes occur as the teeth become older: bone under the teeth changes from cancellous to compact, and the pulp chamber of the tooth is obliterated. Although the labial surface of the dentary lacks a periosteal covering and some of the bone lacks any covering at all, it remains functional throughout the life of the animal.
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  • 108
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 109
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    Journal of Morphology 160 (1979), S. 209-221 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In D. melanogaster the cross-sectioned nerve of the leg-like antenna in the homeotic mutant Antennapedia was ultrastructurally compared with the nerves of the morphologically related second leg and the wild-type antenna. The nerves of the normal antenna and the second leg differ from one another in both the numbers and arrangement of axons. According to these criteria the nerve of the homeotic appendage was structurally identified as a leg nerve.Most of the antennal nerves studied showed a consistent grouping of axons in the profile. This suggests that the assemblage of the axons does not occur randomly, but in an ordered fashion.
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  • 110
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A stress analysis of the primate mandible suggests that vertically deep jaws in the molar region are usually an adaptation to counter increased sagittal bending stress about the balancing-side mandibular corpus during unilateral mastication. This increased bending stress about the balancing side is caused by an increase in the amount of balancing-side muscle force. Furthermore, this increased muscle force will also cause an increase in dorsoventral shear stress along the mandibular symphysis. Since increased symphyseal stress can be countered by symphyseal fusion and as increased bending stress can be countered by a deeper jaw, deep jaws and symphyseal fusion are often part of the same functional pattern. In some primates (e.g., Cercocebus albigena), deep jaws are an adaptation to counter bending in the sagittal plane during powerful incisor biting, rather than during unilateral mastication.The stress analysis of the primate mandible also suggests that jaws which are transversely thick in the molar region are an adaptation to counter increased torsion about the long axis of the working-side mandibular corpus during unilateral mastication. Increased torsion of the mandibular corpus can be caused by an increase in masticatory muscle force, an increase in the transverse component of the postcanine bite force and/or an increase in premolar use during mastication.Patterns of masticatory muscle force were estimated for galagos and macaques, demonstrating that the ratio of working-side muscle force to balancing-side muscle force is approximately 1.5:1 in macaques and 3.5:1 in galagos during unilateral isometric molar biting. These data support the hypothesis that mandibular symphyseal fusion is an adaptative response to maximize unilateral molar bite force by utilizing a greater percentage of balancing-side muscle force.
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  • 111
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 160 (1979), S. 275-297 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nervous system of the planula larva of Anthopleura elegantissima consists of an apical organ, one type of endodermal receptor cell, two types of ectodermal receptor cells, central neurons and nerve plexus. Both interneural and neuromuscular synapses are found in the nerve plexus.The apical organ is a collection of about 100 long, columnar cells each bearing a long cilium and a collar of about 10 microvilli. The cilia of the apical organ are twisted together to form an apical tuft. The ciliary rootlets of the apical organ cells are extremely long, reaching to the basal processes of the cells adjacent to the mesoglea.All three types of sensory cells are tall and slender in profile and are identified by the presence of one or more of the following features: microtubules, small vesicles, membrane-bound granules and synapses. The interneurons are bipolar cells with somas restricted to the aboral end, adjacent to the apical organ. All synapses observed are polarized or asymmetrical.A diagram including all the elements of the nervous system is presented and the possible functions of the nervous system are discussed in relation to larval behavior.
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  • 112
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 159 (1979), S. 117-130 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The purpose of this investigation was to relate the morphology of connective tissues in the mandibular symphysis to the behavioral and experimental evidence for mobility and mechanical stress at the symphysis. The anatomy of the symphysis was examined histologically in 6 mammalian orders encompassing 22 species. Behavioral and experimental evidence of stress during the power stroke of the chewing cycle correspond with stresses at the symphysis implied by the location and orientation of symphyseal connective tissues. These stresses are: (1) dorsoventral shear of the symphysis due to the transfer of force from balancing to chewing sides, (2) bending of the symphysis causing tension along the inferior and compression along superior borders due to torsion on the dentaries from the jaw closing muscles, and (3) antero-posterior shear of the symphysis due to an anteriorly directed stress on the chewing side. Interspecific comparisons suggest that leaf eaters can resist greater dorsoventral shear than fruit or insect eaters, but no correlations exist between diet and bending or antero-posterior shear. This suggests that chewing leaves requires larger biting forces.
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  • 113
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    Journal of Morphology 159 (1979), S. 89-115 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The retina and optic nerve of Strombus luhuanus were examined by transmission electron microscopy in order to provide an ultrastructural basis for their electrophysiological responses, described elsewhere. The retina exhibits a distinct rhabdomeric layer and layers of cell nuclei and neuropile. These layers are comprised predominantly of three cell types that can be readily distinguished on the basis of their shape, their nuclei and cytoplasmic inclusions such as vesicles and filaments. One type of cell, apparently a photoreceptor that depolarizes in response to photic stimulation, possesses a long distal segment with microvilli; such distal segments comprise the bulk of the rhabdomeric layer. A second cell type, which appears to be supportive in function, contains a bundle of tightly packed tonofilaments that extend across the retina from the capsule to the vitreous body; this cell is quite narrow except in the region near the rhabdomeric layer, where it is expanded and wraps around the other cell types. A third type of cell possesses many short microvilli that project from its apical end into the rhabdomeric layer; it may be a second type of photoreceptor or another type of neuron. The retina also contains bundles of cilia that appear to project from a possible fourth type of cell. The layer of neuropile contains numerous processes that exhibit a variety of vesicle types and structures generally associated with synapses; these appear to play a role in mediating inhibitory and excitatory interactions between the retinal neurons. The optic nerve exhibits two populations of fiber distinguishable on the basis of mean diameter. Fibers in these two populations apparently yield “on” and “off” discharges in response to photic stimulation of the eye.
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  • 114
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    Journal of Morphology 161 (1979), S. 145-155 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the parathyroid glands of adult Japanese lizards (Takydromus tachydromoides) in the spring and summer season was examined. The parenchyma of the gland consists of chief cells arranged in cords or solid masses. Many chief cells contain numerous free ribosomes and mitochondria, well-developed Golgi complexes, a few lysosome-like bodies, some multivesicular bodies and relatively numerous lipid droplets. The endoplasmic reticulum is mainly smooth-surfaced. Cisternae of the rough endoplasmic reticulum are distributed randomly in the cytoplasm. Small coated vesicles of 700-800 Å in diameter are found occasionally in the cytoplasm, especially in the Golgi region. The chief cells contain occasional secretory granules of 150-300 nm in diameter that are distributed randomly in the cytoplasm and lie close to the plasma membrane. Electron dense material similar to the contents of the secretory granules is observed in the enlarged intercellular space. These findings suggest that the secretory granules may be discharged into the intercellular space by an eruptocrine type of secretion. Coated vesicles (invaginations) connected to the plasma membrane and smooth vesicles arranged in a row near the plasma membrane are observed. It is suggested that such coated vesicles may take up extracellular proteins. The accumulation of microfilaments is sometimes recognized. Morphological evidence of synthetic and secretory activities in the chief cells suggests active parathyroid function in the Japanese lizard during the spring and summer season.
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  • 115
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    Journal of Morphology 161 (1979), S. 177-183 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of a sex pheromone-producing gland found in the abdomen of Drosophila grimshawi males was studied by light and electron microscopy. This gland, consisting of two intra-anal lobes, contains cells that resemble those of other insect pheromone glands. However, in contrast to many other insect pheromone glands that release pheromone through the cuticle, cells of the intra-anal lobes secrete into a canaliculi-duct system that empties into the anal region. The liquid secretory product flows along the surface of the intra-anal lobes and is brushed onto the substrate by fingerlike projections on the lobes' surfaces.
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  • 116
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    Journal of Morphology 161 (1979), S. 211-219 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nucleoli of rat liver cells duplicate in great detail the lifelong series of reorganizational changes encountered in kidney and intestinal epithelial cells. The ultrastructural components of the large, loosely organized polymorphous nucleoli, which are dominant in the rapidly multiplying stem cells of embryos, are readily accessible for chemical activities. Smaller, more compact amphinucleoli are dominant in more mature cells, which were characterized by Smetana ('70) as “idling” cells, showing slowly continuing ribosome formation and RNP synthesis. In older cells bipartite nucleoli become dominant and are reorganized in increasing numbers from the younger amphinucleoli. These, however, are not replaced in equal numbers from the shrinking pool of polymorphs of young cells which have greatly reduced mitotic potential. Paralleling the shifts in dominant nucleolar types, the high level of protein synthesis declines in older cells not only in the quantity of proteins synthesized but also in kinds of enzymes produced. These fail to meet the structural and functional requirements of aging cells leading ultimately to the onset of age-related degenerative changes. Again it is noted that separation of the karyosomal DNA from the plasmosomal RNA-protein complex of the nucleolus may lead to possible breakdown of the DNA-dependent RNA-protein transcription system ultimately bringing protein synthesis to a very low level in the senescent animal.
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  • 117
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    Journal of Morphology 161 (1979), S. 185-210 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cellular populations present in dorsomedial cortex in the snakes Constrictor constrictor, Natrix sipendon and Thamnophis sirtalis are described at the light microscopic level using Nissl and Golgi preparations as well as at the ultrastructural level. This area plays a central role in cortical organization in snakes by participating in major commissural and association projections.Systematic analyses of Golgi preparations indicate that five populations of neurons are present in dorsomedial area and have a preferential laminar distribution. Layer 1 stellate cells have somata positioned in the center of the outermost cortical layer, layer 1. Their dendrites are confined to this layer. Double pyramidal cells have their somata loosely packed in layer 2. Their dendrites bear a moderate population of spines, ascending through layer 1 to the pial surface and descending partially through layer 3. Some double pyramidal cells have somata displaced downwards into the upper third of layer 3. These neurons closely resemble the layer 2 double pryamidal cells. Layer 3 stellate cells have somata positioned in the middle third of layer 3. Their dendrites extend in all directions throughout layer 3 and through layer 2 into layer 1. Finally, horizontal cells have their somata positioned deep in layer 3, near the ventricle, and dendrites aligned concentric with the ventricle.Comparison of the organization of the known afferents to dorsomedial area with the distribution of the five cell types suggests that the laminations of both afferent fibers and dorsomedial neurons places specific neuronal populations in synaptic contact with specific sets of afferents.
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  • 118
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The heart of Crocodylus porosus is described, and deemed to be typical of living crocodilians after examination of the hearts of Alligator mississippiensis, Caiman crocodilus ssp., Crocodylus johnstoni and Crocodylus n. novaeguineae. Some inconsistencies between the anatomy and supposed patterns of blood flow are discussed. The crocodilian heart is compared with, and seen as an advancement of, the heart of non-crocodilian reptiles. The varanid ventricle is re-examined, as it appeared to contain many crocodilian features, along with the ophidian characteristics described previously. The broad similarities within the three groups are interpreted as adaptations towards a high pressure systemic circulation. Consequently varanids and snakes show the same left and right ventricles, as do crocodilians and birds. The evolution of the complete interventricular septum of crocodilians and birds appears to have involved three major trends: firstly, the development of a high pressure left ventricle and the fusion of most of the combined atrio-ventricular valve to the ostium of the right systemic artery; secondly, a line in which right to left shunting became gradually redundant and the vertical septum was completed to the aortico-pulmonary septum (giving rise to the avian ventricle); and thirdly, a line in which right to left shunting became increasingly important, and the vertical septum completed to the interaortic septum (giving rise to the crocodilian ventricle). Perhaps the crocodilian ancestry included a crocodile that was far more aquatic than any extant species.
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  • 119
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    Journal of Morphology 161 (1979) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 120
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    Journal of Morphology 161 (1979), S. 241-256 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the sacculus and lagena of a moray eel, Gymnothorax sp., was investigated using scanning and transmission electron microscopy. Particular emphasis was placed on the orientation of the sensory hair cells and on the ultrastructure of the sensory cells. The ciliary bundles on the sensory hair cells are of several types, each having a different size relationship between the kinocilium and stereocilia. The cell bodies of the sensory cells are similar to the mammalian type II sensory cell. There were no apparent differences in the cell bodies between sensory cells with different ciliary bundles.Hair cell orientation patterns on the saccular and lagenar maculae differ from patterns found in other fishes. The posterior side of the saccular macula in Gymnothorax has cells oriented dorsally and ventrally, as is typical in other non-ostariophysan species. The anterior end of the saccular macula has alternating groups of anteriorly and posteriorly oriented cells, a situation that differs from the more typical pattern in which anteriorly oriented cells are found on the ventral side of the macula while posteriorly oriented cells cover the dorsal side of the macula. The orientation of cells on the lagena includes ventral cells that are located above a group of dorsally oriented cells. In many other non-ostariophysans, ventrally oriented cells are generally posterior to the dorsally oriented cells.
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  • 121
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Exocrine dermal glands, comparable to the class 3 glandular units of insects, are found in the gills of the grass shrimp, Palaemonetes pugio. The dermal glands are composed of three cells: secretory cell, hillock cell and canal cell. Originating as a complex invagination of the apical cytoplasm of the granular secretory cell, a duct ascends through the hillock and canal cells to the cuticular surface. The duct is divisible into four regions: the secretory apparatus in the granular secretory cell, the locular complex, the hillock region within the hillock cell and the canal within the canal cell. A tubular ductule is contained within the latter two regions. As the ductule ascends to the cuticular surface, its constitution gradually changes from one of a fibrous material to one which possesses layers of epicuticle. During the proecdysial period, the ductule is extruded into the ecdysial space and this is followed by the secretion of a new ductule. Temporary ciliary structures, located near the secretory apparatus of the secretory cell, are associated with the extrusion and reformation of the ductule. Characterized only by a basal body and rootlets throughout most of the intermolt cycle, the ciliary organelles give rise to temporary axonemic processes which ascend through the ductule toward the ecdysial space at the onset of proecdysis. Subsequently, the old ductule is sloughed off and a new ductule is reformed around the ciliary axonemes. Following this reformation, the ciliary axonemes degenerate. The function of cytoplasmic processes, derived from the apical cytoplasm of the secretory cell, is also discussed.
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  • 122
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    Journal of Morphology 162 (1979), S. 1-15 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pineal complexes of the two closely related deep-sea fishes Cyclothone signata and C. acclinidens were compared both qualitatively and quantitatively. Photoreceptor and supportive cells were identified in both species. The deeper-dwelling species, C. acclinidens, had a significantly greater number of photoreceptor-cell outer segment saccules and a higher ratio of receptor cells to nerve fibers in the pineal stalk. It was suggested that these indicate increased photosensitivity of the pineal. Supportive cells were sometimes seen to contain arrays of undulating tubules. The functional significance of these tubules is not understood. A prominent dorsal sac is closely associated with the pineal end-vesicle. Both structures appear to have a common vascular supply suggesting that they are functionally related. Dorsal sac cells contained abundant mitochondria, glycogen, and large filament-like inclusions.
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  • 123
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    Journal of Morphology 162 (1979), S. 37-65 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sialis flavilatera L. (Sialidae, Megaloptera) has telotrophic-meroistic ovarioles. The germ cells of the tropharium are organized into two distinct tissues, the central syncytium and the germ cell tapetum. The central syncytium consists of nurse cell nuclei embedded in a common cytoplasm which is rich in ribosomes and mitochondria. Cell membranes are totally absent. The germ cell tapetum surrounds the syncytium and consists of a monolayer of cells, each of which is connected with the central syncytium by an intercellular bridge. The oocytes differentiate from basal tapetum cells by previtellogenic growth. Their nutritive cords remain connected to the central syncytium by the intercellular bridge.Ovariole development starts soon after hatching with the immigration of germ cells into the ovariole-anlagen and is finished during pupal stages 23 months later. In apical regions of each tropharium, mitoses occur throughout larval life. The descendants enter the prophase of meiosis which lasts until pre-vitellogenesis; thus, a differential gradient of position and time is established. About 12 months after hatching, the central syncytium arises at the base of the tropharium from a membrane labyrinth in which intercellular bridges are entangled. Evidence is presented that endopolyploidization does not occur during germ cell differentiation.Finally, the results are compared with those found in Hemiptera and polyphage Coleoptera. The great diversities are interpreted as an indication for a polyphyletic origin of the telotrophic ovary.
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    Journal of Morphology 162 (1979), S. 249-273 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To gain insight into the multiple functions of a complex biological structure, the morphology of the pharynx of the larva (ammocoete) of the lamprey Petromyzon marinus was investigated with scanning electron microscopy and histochemistry (PAS and Alcian blue). Features studied include the gills, the parabranchial chambers external to the gills, intrapharyngeal ciliary tracts, the ridged pharyngeal roof, the floor, and the intrapharyngeal taste buds. Significant findings are: (1) All (nonciliated) cells lining these structures are covered with microvilli or microridges. The pattern and packing density of these membrane features vary among different pharyngeal structures. The lumenar membranes of pharyngeal lining cells overlie a mucous prosecretion in the apical cytoplasm, suggesting that the microvilli/ridges on these membranes function to anchor mucus. (2) Patterns of microvilli/ridges on the gill respiratory lamellae differ among ammocoetes of different species. (3) Pharyngeal osmo-regulatory cells (“chloride cells”) could not be identified on the basis of the microvillus/ridge pattern. (4) Two types of ciliary tracts are present within the pharynx. One has tall (x= 13 μm) and densely packed cilia, whereas the other has shorter (x= 7 μm) and less densely packed ones. Because mucus covers both types of tracts their function appears to involve the transport of mucus. (5) Food particles were found on the lateral surfaces of the gill filaments and on the surfaces of the parabranchial chambers. It appears that goblet cells in the epithelia of these regions secrete mucus in which the particles are trapped.
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    Journal of Morphology 162 (1979) 
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  • 126
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    Journal of Morphology 162 (1979), S. 413-424 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Two-toed sloths have evolved a wrist complex that includes the following traits: (1) diminution and distal migration of the pisiform, with a loss of contact with the ulna; (2) reduction of the distal end of the ulna to a styloid process; and (3) extremely reduced contact between the ulna and triquetrum. These traits were proposed by Lewis ('65, '74) to be indicative of brachiating habits and to be a unique adaptation of the Hominoidea. Cartmill and Milton ('77) recently found a similar complex in the wrists of the lorisines. Very similar adaptations of the wrist among the Hominoidea, lorisines, and two-toed sloths clearly refute contentions of Lewis and strengthen the hypothesis of Cartmill and Milton that the traits common to those animals are due to similar slow, cautious, but acrobatic locomotion.
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  • 127
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    Journal of Morphology 162 (1979), S. 425-451 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gross morphology, histology and ultrastructure of the canary's incubation patch and the ventral apterium from which it arises are described. The apterium is vascularized by pectoral, external mammary, incubation, and prepubic arteries. It is innervated by cutaneous branches of spinal nerves. It has a surface area of 6 cm2.Its epidermis is a stratified squamous epithelium with basal, intermediate, transitional and cornified layers. Cells in the stratum germinativum contain a normal array of organelles, but are characterized by tonofilaments, desmosomes and interdigitating surfaces. Cellular organelles disappear in the stratum transitivum and are replaced by large vacuoles and keratohyalin bands. Nonmyelinated nerve fibers are abundant in the stratum germinativum.The dermis consists of (1) an avascular layer of dense collagen subjacent to the epidermis and containing many nonmyelinated nerves, and (2) an underlying layer of areolar connective tissue containing blood vessels, lamellar corpuscles and nerves. A layer of coarse elastic fibers, reinforced by collagen and smooth muscle, separates the dermis from subcutaneous tissue.In contrast to the ventral apterium, the incubation patch is featherless and visibly hypervascular and edematous. Its epidermis is both hypertrophic and hyperplastic. Large spaces separate cells in the stratum germinativum. The visible hypervascularity is due to hyperemia and increased number and size of blood vessels in the dermis. Visible edema is due to the accumulation of fluid interstitially. Although no histological differences exist among various regions of the ventral apterium, such differences are present in the incubation patch.
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  • 128
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    Journal of Morphology 162 (1979), S. 453-463 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Haematoxylin, Alcian Blue-Chlorantine Fast Red (ABCR) and the Ralis osteoid-specific stain were employed to closely follow the histogenesis of the tibia of the embryonic chick so as to provide an accurate description of the onset of ossification.An overview of the major cytological events preceding osteogenesis in the tibia was obtained from hindlimbs of embryos of H. H. (Hamburger and Hamilton, '51) stages 16-26 (2.5-5 days of incubation) stained with ABCR. A description of the cytological changes in the periosteum as it develops from the perichondrium and an analysis of the timing of the onset of osteoid deposition was obtained from the tibiae of accurately aged and staged embryos of H. H. stages 28-32 (5.5-8 days). These tibiae were stained specifically for the detection of osteoid:the freshly-secreted, unmineralized product of fully-differentiated osteoblasts. The perichondrium transformed into a bi-layered periosteum at H. H. late stage 29 (6.5 days) while osteoid was first detected adjacent to the hypertrophic cartilage of H. H. stage 30 (6.5-7 days) tibial diaphyses.These results, correlated with the immunoflourescent studies of Von der Mark et al. ('76a,b), which revealed the presence of Type I (bone-type) collagen-synthesizing cells in the perichondria of tibiae from embryos of H. H. stage 28 (5.5-6 days), demonstrated that the onset of determination of cells for osteogenesis and the cytodifferentiation of the periosteum are not temporally coupled.
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    Notes: The three major salivary glands of the monotreme echidna are described. The parotid is a typical serous gland with tubulo-acinar secretory endpieces and a well-developed system of striated ducts. The mandibular gland, although light microscopically resembling a mucous gland, secretes very little glycoprotein. Its cells are packed instead with serous granules, resembling in fine structure the “bull's eye” granules in the mandibular gland of the European hedgehog Erinaceus europaeus. The sublingual glands secrete an extremely viscous mucous saliva. Expulsion of this saliva through the narrow ducts is probably aided by contraction of the extensive myoepithelial sheaths surrounding the secretory tubules. Application of the glyoxylic acid induced fluorescence method failed to demonstrate adrenergic innervation in any of the glands.
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    Journal of Morphology 159 (1979) 
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    Journal of Morphology 159 (1979), S. 233-243 
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Patterns of tracheation in the abdominal central nervous system and the cerci of Acheta domesticus are described from whole mounts, and light and electron microscopy.The tracheal supply of the ganglia is derived from ventral longitudinal tracheal trunks which have segmental connections to the spiracels. Each abdominal ganglion is served by a single pair of tracheal trunks, except the terminal ganglion, which has two pairs. Within the ganglia, tracheoles occur principally in association with glia-rich areas of the neuropile. We suggest that the respiratory exchange may be concentrated in the cell bodies of neurons and glia. Each cercus has a tracheal supply in paralle with a large air sac which, it is suggested, serves to lighten the cercus, functions as a resonator for sound reception, or facilitates tidal flow of hemolymph and postecdysial expansion of the cercus. No tracheae run continuously between ganglia or between the terminal ganglion and the cerci, and they do not appear to have a potential role as a contact guidance pathway for cercal nerve growth.
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    Journal of Morphology 159 (1979), S. 343-353 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The effect of germanium on the secretion of siliceous spicules by the freshwater sponge Spongilla lacustris was investigated by exposing germinating and hatching gemmules to varying concentrations of germanium (Ge) in the presence of silicon (Si). Results were analyzed quantitatively and qualitatively and demonstrate that a [Ge]/[Si] (= molar ratio) of 1.0 completely inhibits silicon deposition. Intermediate ratios (0.5, 0.1, 0.01) which are permissive to spicule appearance result in fewer, shorter, and thinner spicules, in proportionately fewer microscleres, and in short bulbous megascleres. The size of the bulb increases with increasing [Ge]/[Si], while the length of the bulbous megascleres decreases with increasing [Ge]/[Si]. Microscleres do not demonstrate these graded responses suggesting that they are secreted in an all or none manner. Swellings produced in pond water and bulbs produced in germanium appear to decrease in size with time indicating a spreading of the accumulated silica. The effect of germanium on spicule secretion can be partially explained by its ability to uncouple the growth in length of the axial filament from the growth of the surrounding silicalemma. Under these conditions excess silicalemma is produced in which silica accumulates as bulbs in short spicules. Continuous exposure to Ge is necessary to produce this altered morphology. It is conjectured that the bulbs may be retained due to an inhibition of spreading. which in turn may be caused by the incorporation of germanium into the silica.
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    Journal of Morphology 160 (1979), S. 143-163 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The chloride cells in the interlamellar areas of the gills of young adult, anadromous sea lampreys, Petromyzon marinus L., captured in fresh water undergo structural modification during the adaptation of these animals to sea water. In fresh water the chloride cells are partially overlapped by mucus-secreting superficial cells and contain an extensive reticulum of cytoplasmic tubules, which are confluent with both lateral and basal plasma membranes, numerous mitochondria, a Golgi complex of moderate size, and numerous apical vesicles. Adaptation to sea water results in a retraction of the superficial cells, exposing the entire apical surface of the chloride cells, and a proliferation of both cytoplasmic tubules and mitochondria. Extensive enlargement of the Golgi complex in the chloride cells of these animals suggests the involvement of this organelle in the proliferation of cytoplasmic tubules. The extracellular tracer, ruthenium red, enters the tubules from the lateral or basal intercellular spaces in both freshwater- and seawater-adapted animals but never enters either tubules or vesicles from the apical surfaces, indicating that these are not confluent. The presence of dividing basal cells and newly-forming chloride cells, combined with evidence of degeneration of chloride cells, suggests that there is a turnover of this cell type. Both superficial and basal cells are phagocytic and involved in heterophagy of degenerating chloride cells. This phenomenon occurs in both fresh water and sea water indicating that the chloride cells may be functional in both environments.
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  • 134
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    Journal of Morphology 160 (1979), S. 169-193 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A detailed account is given of the structure of the gills of Clarias batrachus, Heteropneustes (= Saccobranchus) fossilis, Channa punctata, Monopterus (= Amphipnous) cuchia and Boleophthalmus boddaerti, based upon light and electron microscopy. In all five species the basic organization into primary and secondary lamellae is apparent but the latter are very much more modified in Monopterus.Three main layers separate the water and blood on the surface of the secondary lamellae. The outer epithelium is usually two layered but may be multilayered close to the origin of the secondary lamellae from the gill filament. The basement membrane is relatively thin and a middle dense layer containing collagen fibrils separates two clear layers. The pillar cells, so characteristic of secondary lamellae, are present in all except Monopterus and flanges from these cells surround the blood channels with the exception of the marginal channels. The latter are lined by endothelial cells which line all the blood channels of Monopterus.The overall thickness of the three layers comprising the water/blood barrier ranges from 1.5 to 13 microns. A number of modifications to this basic organization can be related to the degree of dependence of the different species on air-breathing.Boleophthalmus is the only species commonly found in brackish water and its secondary lamellae have well developed lymphoid spaces between two layers of the epithelium. Special densely-stained regions of the pillar cell flanges were also present in this fish and may have a supporting function.
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    Journal of Morphology 159 (1979), S. 17-27 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Eggs of Chelydra serpentina were shifted during incubation between the female producing temperatures of 20°C or 30°C and the male producing temperature of 26°C. In the 20°C and 26°C combination, the stages during which incubation temperature determined sex were stage 14 through stage 16 (stages of normal series, Yntema, '68). In the 30°C and 26°C combination, the temperature sensitive stages for sex determination were stage 14 through stage 19. Incubation at 26°C throughout this period was needed to produce all males. Incubation at 30°C during either the first or second half of the period produced nearly all females; shorter periods of incubation at 30°C were more effective in producing females during the second half of the sensitive period. In the 20°C and 26°C combination, incubation at 20°C or 26°C for parts of the sensitive period produced both males and females. In three of the 57 clutches of eggs used in the experiments, incidence of females was atypically high.
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    Journal of Morphology 159 (1979), S. 29-47 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Early spermatids of the onychophoran Peripatopsis capensis are spherical cells with a centrally located nucleus, numerous mitochondria, Golgi complexes, microtubules and two centrioles. During spermiogenesis, Golgi vesicles migrate to one side of the cell where they form a tight aggregate, which is later shed. The mature spermatozoon has no acrosome. Several mitochondria fuse to form a middle piece containing three large mitochondria. Nucleus and middle-piece elongate, presumably under the influence of helically twisted microtubules. Outside this set of microtubules a continuous layer of endoplasmic reticulum cisternae is formed which separates the interior portion of the cell from an external cytoplasmic rim, which is later shed. Outside the 9 + 2 complex, the tail presents nine accessory microtubules, and a peripheral layer of microtubules beneath the plasma membrane. The enforcement of the tail structure may be related to the fertilization biology of this animal, which is by “hypodermal” impregnation.
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    Journal of Morphology 159 (1979), S. 67-79 
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    Topics: Biology , Medicine
    Notes: The distribution and morphology of phagocytic (Type II) supraependymal cells residing within the third ventricle of the guinea pig were investigated by scanning electron microscopy. Type II supraependymal cells were restricted to nonciliated regions of the ventricle. They were most numerous on the choroid plexus, abundant within the infundibular recess and were present on the ventricular floor in the region of the median eminence. Morphologically, they were characterized by a soma from which pseudopodia-like processes extended to the subjacent ependyma. Type II cells varied in configuration according to their location. Those residing on the choroid plexus typically had irregular somas and possessed processes that generally terminated in finger-like extensions. In contrast, cells on the ventricular floor and within the infundibular recess were stellate and possessed processes that terminated in fan-like cytoplasmic expansions. There were no differences noted in the frequency, distribution or morphology of Type II supraependymal cells in male and female animals. Furthermore, cell frequency did not appear to vary in relation to the estrous cycle. The data suggest that the pleomorphism exhibited by Type II supraependymal cells may reflect adaptations to diverse environmental conditions present within different regions of the third ventricle.
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    Journal of Morphology 161 (1979) 
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  • 139
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    Notes: A detailed morphometric study of the basilar membrane was made from serial sections and graphic reconstructions of the cochlea of three little brown bats. Four distinct morphometric changes were observed within the basilar membrane. First, between 0-1.4 mm from the basal end of the cochlea, there is a rapid increase in width and cross-sectional area of the basilar membrane. Secondly, between 1.4-2.5 mm, there is little change in width of the basilar membrane (its cross-sectional area is at its greatest in this region). Thirdly, between 2.7-3.1 mm, there is a sudden decrease in cross-sectional area concomitant with an increase in the width of the basilar membrane. Finally, between 3.1 mm and the apex, there is a gradual decrease in cross-sectional area concomitant with an increase in the width of the basilar membrane. The magnitudes of the cross-sectional areas of the scalae media and vestibuli decrease from base to apex, but this is not true for the scala tympani. The cross-sectional area of the scala tympani appears to decrease from the base to 0.7 mm, then it increases up to 1.4 mm, and then it decreases to the apex. These morphometric changes in the basilar membrane of the little brown bat are compared to those in other echolocating and non-echolocating mammals. The significance of these changes is discussed in relation to the range of hearing in the little brown bat.
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    Notes: The combined techniques of light microscopy, scanning (SEM) and transmission (TEM) electron microscopy were used for the first time to study the structure of unicameral lungs of a Tegu lizard (Tupinambis nigropunctatus). The lungs are prolate spheroid bags with blood supplied by superficial branches of a dorsal pulmonary artery and returned by diffuse, more deeply located veins. The primary bronchus enters the medial aspect near the apex of the lung. The lung wall is composed of trabeculae: (1) arranged in a faviform pattern, (2) forming individual faveoli (gas exchange chambers) which appear deepest in the cranial one-half of the lung, (3) all of which have a smooth muscle core overlain by either a ciliated or nonciliated epithelium. A ciliated epithelium lines the luminal surfaces of the large primary trabeculae and parts of smaller secondary trabeculae; it is composed of cone-shaped cells with ciliated-microvillous surfaces, and of columnar serous secreting cells. Nonciliated epithelium covers the luminal surface of portions of some secondary trabeculae, abluminal surfaces of primary and secondary trabeculae and all surfaces of the small tertiary trabeculae forming the faveoli. The nonciliated epithelium overlies an extensive superficial capillary network. The blood-gas barrier (0.7-1.0 μm thick) is composed of a thin cytoplasmic flange of Type I pneumonocytes, a thick homogeneous basal lamina and an attenuated endothelial cytoplasm. Numerous surfactant-producing Type II pneumonocytes are closely associated with the Type I pneumonocytes. The nonrespiratory ciliated epithelium may function in humidification of air and clearing of the lungs.
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    Journal of Morphology 161 (1979), S. 309-321 
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    Notes: Rhabdomeric microvilli of the housefly were freeze-fractured (FF) and thin sectioned (TS) for ultrastructural examination. Ordered files of closely packed membrane particles (82 Å wide, 250 Å long) were seen (FF) on the microvillar membrane (usually E face). The long axis of each particle was canted about 45° to that of the microvillus. Occasionally particles in this array appeared on the P face. It is hypothesized that ordered particles may represent either a photopigment precursor stock, a second photolabile pigment, or the newly discovered sensitizing, UV-absorbing, photostable visual pigment. In the underlying membrane leaflet (P face) were found spherical (85 Å diameter) unoriented particles in a concentration of about 6,000/μm2. The size, shape and density of these structures are compatible with those of rhodopsin particles. These particles also covered the basal area of each microvillus. The findings from TS material were difficult to correlate with those from FF replicas. At high magnification the former showed that the plasma membrane of the transected microvillus is composed of spherical, hollow subunits (averaging 43 Å diameter), sometimes fused to form double, 86 Å units. These substructures were closely packed and continuous around the microvillus. This beaded plasma membrane, in rare cases, was doubled around the microvillus. In other instances the plasma membranes were continuous between neighboring microvilli. The physiological implications of these ultrastructural features are discussed.
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    Journal of Morphology 161 (1979), S. 323-335 
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    Notes: The blood supply of muscle spindles was studied in serial cross sections in macaque, cat, rabbit, guinea pig, mouse and pigeon muscles which had been incubated in a medium containing 3,3′ diaminobenzidine. Lumina of blood vessels were recognized by the reaction product that was localized within erythrocytes. The outer capsule was well vascularized, but few or no capillaries were seen in the periaxial space. The inner spindle capsule, which closely invests the axial bundle, was rarely contacted by periaxial capillaries at the equator and juxtequator. Capillaries occurred more frequently adjacent to intrafusal fibers at the polar region and beyond the end of the outer capsule. Shorter diffusion distances and, usually, higher capillary densities were found at the polar region than at the spindle midsection. This suggests that transcapillary exchange at the polar segment is nearer to conditions prevalent in extrafusal muscle than elsewhere in the spindle, provided the inner and outer capsules are not less permeable at the poles than at the midsection. Differences in blood supply among mammalian species appear to be related to receptor size.
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    Journal of Morphology 161 (1979), S. 337-345 
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In considering primate and hominoid phylogeny, the fundamental position assigned to opossums is explained partially by the characteristic morphology of their hands and feet. One of the main functional features of the human hand is the ability to make a stabilized arch of the finger. Because the extensor assembly plays a key role in establishing an arched finger, the extensor systems of the digits of both the hands and feet were studied in two species of opossum, Philander opossum and Didelphis marsupialis.In the foot, two extensor tendons join in each toe to form one tendinous plate, which inserts onto the base of the second phalanx. Lumbricals join this plate along the tibial side, and interosseus insertions are found, although a true interosseus wing is lacking. At the proximal interphalangeal level, a terminal tendon takes its origin from this tendinous plate. This terminal tendon is oval in cross-section and contains elastic structures. Oblique bands arise from this terminal tendon and run proximally along the proximal interphalangeal joint inserting onto the base of the first phalanx. There are elastic structures in the flexor tendon on the dorsal side near its site of insertion.In the hand, the main extensor tendons are arranged differently and the interossei contribute substantially to the extensor assembly. Otherwise, the extensor assembly of the hands and feet are quite similar. The function of the so-called paratendinous intravaginal flexors is discussed as are evolutionary aspects of the extensor assembly.
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    Journal of Morphology 162 (1979), S. 275-309 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to provide an ontogenetic basis for the establishment of tetrapod muscle homologies and for the analysis of complex mammalian muscle states, a descriptive analysis of the morphogenesis of the thigh of Mus musculus has been made. The pattern and sequence of muscle cleavage and the migrations of individual muscle primordia are characterized from the eleventh day of gestation, when cleavage begins, through early neonatal stages. Observations on skeletal differentiation and lumbosacral plexus formation are also included. Thigh muscle morphogenesis is compared to that in the lizard, Lacerta, (Romer, '42) and the chick (Romer, '27) and homologies identified. An ontogenetic basis for the definition of ancestral and derived muscle states is provided in muscles that are morphologically variable in mammals. These include the gluteus minimus, gracilis, adductor brevis and several hamstring muscles. Certain muscles that show variable innervation patterns in adult mammals, i.e., pectineus, quadratus and adductor magnus, typically develop from premuscle regions that separate muscle anlagen innervated by different nerves. Two muscle anlagen appear in the embryonic mouse thigh and then disappear late in prenatal or early postnatal development. Comparisons with other mammals, especially the marsupial, Marmosa, reveal that these muscles are phylogenetic vestiges that degenerate before maturity. A sartorius vestige is identifiable through the thirteenth day of gestation. A tenuissimus anlage is present until shortly after birth and is clearly innervated by a branch of the peroneal nerve.
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  • 146
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    Journal of Morphology 162 (1979), S. 311-311 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 147
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cell surface coats are important in adhesion and other cellular activities. The lamprey egg possesses a surface coat that has been divided into two morphologically and functionally distinct regions. The amorphous apical tuft forms a cap over the animal pole, while the elaborately-textured adhesive coat covers the ventral two-thirds of the egg. This latter area is composed of saccules that form rosettes over the egg surface and is derived from the remains of specialized follicular cells which break down during ovulation. The adhesive qualities of these coats may be inhibited or abolished by various proteins and sulphydryl-blocking agents, thereby implicating, as a possible source of this adhesion, classes of acid and sulphated glycoproteins and glycosaminoglycans which occur on the egg surface.
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  • 148
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    Journal of Morphology 162 (1979), S. 327-341 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structure of ankylotic teeth in Xenopus laevis was studied by light, transmission, and scanning electron microscopy as well as by microradiography in decalcified and undecalcified specimens.The mature teeth of Xenopus laevis are calcified from the crown to the base, fused to the jaw bone, and have no uncalcified area, such as a fibrous ring separating the tooth into the crown and pedicle. Microradiography shows that the mature tooth and jaw bone appear as an X-ray opaque area, except for the basal region of the dentine. This region is composed of an X-ray translucent area and an X-ray opaque thin layer on the lingual side of the translucent area. The mature tooth is composed of two differently calcified areas: (1) a highly calcified area, which makes up almost all of the tooth and contains a thin layer of the basal dentine on the lingual side, and (2) a lowly calcified basal dentine, which is fused to the jaw bone. Therefore, the lowly calcified area does not completely separate the dentine and jaw bone.Repeating banding patterns among the collagen fibrils differ among the dentine-forming area and the matrices of dentine and jaw bone. During the formation of ankylosis of the tooth germ, collagen bundles in the dentine-forming area accumulate directly on the surface of the jaw bone. Consequently, the mature teeth of Xenopus laevis fuse to the jaw bone directly without the mediation of the other structures.
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  • 149
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: Agar cultures of CBA fetal liver, peripheral blood, yolk sac and adult marrow cells were stimulated by pokeweed mitogen-stimulated spleen conditioned medium. Two to ten percent of the colonies developing were mixed colonies, documented by light or electron microscopy to contain erythroid, neutrophil, macrophage, eosinophil and megakaryocytic cells. No lymphoid cells were detected. Mean size for 7-day mixed colonies was 1,800-7,300 cells.When 7-day mixed colonies were recloned in agar, low levels of colony-forming cells were detected in 10% of the colonies but most daughter colonies formed were small neutrophila and/or macrophage colonies. Injection of pooled 7-day mixed colony cells to irradiated CBA mice produced low numbers of spleen colonies, mainly erythroid in composition. Karyotypic analysis using the T6T6 marker chromosome showed that some of these colonies were of donor origin. With an assumed f factor of 0.2, the mean content of spleen colony-forming cells per 7-day mixed colony was calculated to vary from 0.09 to 0.76 according to the type of mixed colony assayed.The fetal and adult multipotential hemopoietic cells forming mixed colonies in agar may be hemopoietic stem cells perhaps of a special or fetal type.
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  • 150
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    Journal of Cellular Physiology 98 (1979) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 151
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Notes: Non-lethal concentrations of bromodeoxyuridine induce a 2- to 5-fold increase in the specific activity of alkaline phosphatase in HeLa subclone, S3G. Experiments employing 10-hour pulses of BRdU showed that 48 hours were required before induction commenced, and that maximal induction was attained by 96 hours. Under conditions in which DNA synthesis was prevented with hydroxyurea induction did not occur. Upon removal of hydroxyurea both DNA synthesis and induction were rapidly reestablished. Furthermore, experiments employing radiolabelled BRdU demonstrated that the kinetics of the induction process paralleled the incorporation of the analogue into cellular DNA.These results indicate that DNA synthesis, or some process intimately linked to DNA synthesis, is required for the induction of alkaline phosphatase, and suggest that the mode of the induction may be through the incorporation of the analogue into cellular DNA.
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  • 152
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Preincubation of C57BL adult marrow cells or CBA fetal liver cells with a 250-fold excess concentration of purified GM-CSF failed to reduce the frequency of cells forming eosinophil, megakaryocyte or erythroid colonies in subsequent agar cultures. When excess concentrations of purified GM-CSF were added to agar cultures stimulated by pokeweed mitogen-stimulated spleen conditioned medium (SCM), no reduction was observed in the frequency of eosinophil, megakaryocyte or erythroid colonies. Addition of 4 units of purified erythropoietin (EPO) to cultures of fetal liver or adult marrow cells stimulated by SCM increased the number of erythroid colonies but did not reduce the number of non-erythroid colonies or the non-erythroid content of mixed erythroid colonies.Although neither GM-CSF nor EPO alone was able to stimulate erythroid colony formation in agar cultures of fetal liver cells, small numbers of large erythroid colonies were stimulated to develop in cultures containing both purified regulators. Purified GM-CSF was also able to support the survival in vitro of a small proportion of erythroid colony-forming cells in fetal liver populations cultured initially in the absence of SCM and the survival of some eosinophil and megakaryocyte colony-forming cells in similar cultures of adult marrow cells.The results do not support the hypothesis that GM-CSF and EPO compete for a common pool of uncommitted progenitor cells. On the contrary, the data indicate that GM-CSF and EPO are able to collaborate in stimulating the proliferation of some erythropoietic cells. Furthermore, purified GM-CSF appears to be able to support temporarily the survival and/or initial proliferation of at least some cells forming erythroid, eosinophil and megakaryocyte colonies, even though GM-CSF is unable to stimulate the formation of colonies of these types.
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  • 153
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    Journal of Cellular Physiology 99 (1979), S. 175-182 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Follicle stimulating hormone (FSH) stimulates “colony formation” by immature rat Sertoli cells in primary culture. “Colony formation” involves cell aggregation. Consequently, the involvement of cell surface glycoproteins in cell aggregation was investigated by treatment of dissociated 10-day rat testis cells with sodium metaperiodate, glucosamine, various lectins, tunicamycin, and puromycin. Treatment of control cultures with 5 μM glucosamine stimulated cell aggregation; however, glucosamine did not affect FSH-stimulated cultures. Treatment of dissociated testis cells with 5 μM sodium metaperiodate, 10 μg/ml castor bean agglutinin (ricin), or 2.5 μg/ml horseshoe crab agglutinin inhibited FSH stimulation of cell aggregation. A similar inhibition of cell aggregation was observed following addition of 10 μg/ml puromycin or tunicamycin to culture media from 0- to 18-hours incubation. Treatment with soybean agglutinin, concanavalin A, or wheat germ agglutinin had no effect. The galactose-specific lectins, Ricin, Ricinus communis agglutinin I, and Bendeirea simplicifolia agglutinin, inhibit the FSH stimulation of 3H-aminoacid incorporation as well as cell aggregation in 24-hour cultres. The inhibition of cell aggregation by sodium metaperiodate treatment was reversed with 5 μM sodium borohydride reduction. Sodium metaperiodate treatment did not alter cell viability (as assayed with trypan blue dye exclusion), did not alter cell attachment, nor significantly decrease 125I-FSH binding by cultured testis cells. The results suggest that FSH stimulation of cell aggregation by immature rat Sertoli cells requires cell surface glycoprotein interactions. Furthermore, the specificity of lectin inhibition suggests that glycoproteins with terminal galactose and sialic acid residues are required for the FSH induction of cell aggregation.
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  • 154
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    Journal of Cellular Physiology 99 (1979), S. 191-199 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Vero (African green monkey kidney) cells grown in tissue culture monolayer were sensitive to Clostridium perfringens enterotoxin. Within 30 minutes of exposure to the enterotoxin gross morphological damage was observed and within 40 minutes approximately 75% of the cells had detached. Nearly half of the cells were nonviable following 35 to 40 minutes incubation with the enterotoxin. Doses as low as 0.1 ng caused small but detectable inhibition of plating efficiency of the cells while more than 100 ng caused the inhibition to approach 100%. Total inhibition of DNA, RNA, and protein synthesis occurred within 30 minutes exposure to enterotoxin. Heat inactivated enterotoxin had no apparent effects upon cellular morphology, detachment, viability, plating efficiency, or incorporation. We propose that the enterotoxin induces structural damage to the cytoplasmic membrane which results in loss of electrolytes and other essential substances from the cells. The outcome of this process is shut down of macromolecular synthesis, gross morphological damage, and eventual death of the cell.
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  • 155
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    Notes: The sulfated mucopolysaccharide composition of normal and virus transformed Balb 3T3 and BHK21 cell lines is reported. It is shown that normal 3T3 cells contain mainly chondroitin sulfate B and heparitin sulfate. Relatively higher amounts of chondroitin sulface AC were observed in polyoma virus transformed 3T3 cells, besides an absolute increase of all the three sulfated mucopolysaccharides in the polyoma and SV 40 transformed cells. It is shown also that the three sulfated mucopolysaccharides are at least in part at the cell surface. Similar differences in sulfated mucopolysaccharide composition of normal and virus transformed BHK cell lines were also observed.
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  • 156
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    Journal of Cellular Physiology 98 (1979), S. 491-502 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The removal of serum from the medium of ovarian granulosa cells in exponential or confluent stages of growth results in a rapid and pronounced decrease in the rate of transport of the non-metabolizable amino acid, α-aminoisobutyric acid. This decrease is rapidly and completely reversed by the addition of serum. The decrease and its reversal are insensitive to inhibitors of RNA and protein synthesis and are unaffected by a number of other metabolic inhibitors. The serum requirement cannot be replaced by peptide hormones known to stimulate cell division and secretion by these cells. These data are consistent with a model of post-translational control of AIB transport by a high-molecular-weight component of serum.
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  • 157
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    Journal of Cellular Physiology 99 (1979), S. 333-341 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Glucocorticoids induce several phenotypic changes in rat hepatoma cells in tissue culture, including the inhibition of plasminogen activator activity. Variant cell lines resistant to dexamethasone inhibtion of plasminogen activator activity have been isolated using an agar-fibrin overlay technique to identify colonies with fibrinolytic (plasminogen activator) activity. The variants are resistant to concentrations of dexamethasone 1,000 times that necessary to completely inhibit plasminogen activator activity in wild-type cells. The variant phenotype has been inherited in a stable manner for more than 300 generations in continuous culture in the absence of dexamethasone. These variants are unique in that the resistance is not secondary to defective or absent glucocorticoid receptors but is due to a lesion specific for regulation of plasminogen activator. Fluctuation analyses support the hypothesis that resistance to dexamethasone arises randomly and is not induced by dexamethasone. Because HTC cells are heteroploid and karyotypically highly variable, variants are thought to arise primarily by chromosomal segregation events. These variants provide a valuable tool for studying the mechanism of hormonal regulation of plasminogen activator as well as the role of proteases in hormonal regulation of membrane functions.
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  • 158
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    Journal of Cellular Physiology 99 (1979), S. 349-357 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Autophosphorylation of 3T3 cells, utilizing endogenous membrane protein kinase, can be detected by incubating the cells with μgM32P-ATP. The phosphorylation activity of growing cells is two to four-fold greater than quiescent ones. In this study, the increased phosphorylation activity of serum-stimulated cells was examined. Phosphorylation, measured at times after serum stimulation of quiescent cultures, was found to increase in early G1 and to reach a maximum prior to DNA synthesis. This increase in stimulated cells was dependent on RNA and protein synthesis but not on DNA synthesis. The increased activity decayed quickly (half-life approximately 2-3 hours) in the presence of cycloheximide, while the basal activity in quiescent cells was relatively unchanged. Insulin, prostaglandin E1 or prostaglandin F2α were also found to bring about the same increase in phosphorylation as serum, although in contrast with serum they caused only a small percentage of the culture to synthesize DNA. The results suggest that enhanced phosphorylation activity is a G1 event. It does not depend on subsequent DNA synthesis. Phosphorylation may be one of the biochemical steps in G1, necessary but not sufficient for cells to move into S phase.
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  • 159
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    Journal of Cellular Physiology 99 (1979), S. 359-367 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mitotic HeLa cells (M cells) synthesize protein at about 25% of the rate of S phase cells. This decrease in protein synthesis is due to a reduction in the rate of initiation. However, extracts prepared from M cells are almost as active in protein synthesis as S cell extracts. Both cell extracts are quite active in in vitro initiation of protein synthesis. Moreover, two steps in initiation, binding of Met-tRNAf to 40S ribosomal subunits and binding of mRNA to ribosomes, show similar activity in both extracts. The difference in protein synthesizing activity observed in vivo is largely eliminated in the preparation of cell-free systems. The ribosomes of M cells contain small mot wt RNA, which inhibits protein synthesis in vitro. This RNA, which has possibly a nuclear origin, may be a cause of the reduction in the rate of protein synthesis in M cells.
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  • 160
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    Journal of Cellular Physiology 99 (1979), S. 369-381 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Friend erythroleukemic cells can be induced by a variety of agents to synthesize hemoglobin and to exhibit other characteristics suggesting erythroid maturation. Upon induction of hemoglobin synthesis with dimethyl-sulfoxide (DMSO), the chloride flux in Friend cells gradually increases, until after five days of exposure to DMSO (when the hemoglobin content of the cells approaches that of the mature erythrocyte) the flux is three times the value in non-induced cells. A similar flux increase is observed in the presence of a different type of inducer, hypoxanthine, but no increase in flux is seen in the mutant cell line, TG-13, which does not synthesize hemoglobin after DMSO treatment. Thus, the flux increase seems to be associated with the induction process, rather than being a direct effect of the inducing agent. After DMSO treatment, the sulphate flux decreases and the chloride/sulphate selectivity increases, as would be expected if the cells were becoming more like red cells. On the other hand, the sensitivity of the chloride flux to the inhibitor, furosemide, and to temperature is the same in the induced as in the non-induced Friend cells, and different from that of the mature red cell. Thus, the anion transport properties of the induced Friend cell are different from those of both the non-induced Friend cell and the mature erythrocyte. Either the system in the induced cell represents an intermediate stage in the development of the mature red cell characteristics, or else the maturation of transport function in the Friend cell differs from that in normal erythrocyte precursors.
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  • 161
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: Heat-synchronized Tetrahymena pyriformis have been subjected to 5-, 15- and 30-minute pulses of hydrostatic pressure in the range 100-300 atm, without being simultaneously subjected to significant heats of compression. The pressure-induced division delays depend on (1) the level of pressure used, (2) the length of pressure pulse and (3) the time after the synchronizing treatment at which the pressure is applied. A pressure-dependent inhibition of 3H-leucine incorporation into protein was also measured. Comparison of the effects of pressure with those of pulse treatments of cycloheximide and emetine on cell division and protein synthesis revealed that the physical agent produced characteristically different responses from those of the chemical agents. Of particular interest was the fact that the division delays induced by pressures of 200 atm and above were greater than those observed after treatments with cycloheximide and emetine which produced comparable levels of protein synthesis inhibition. Pressure also delayed cells if it was applied at a time when addition of chemical inhibitors had little effect on the first synchronous division. The results show that inhibition of protein synthesis by pressure cannot entirely account for pressure-induced effects on cell division. The possibility that pressure may also directly affect other processes, such as the assembly of proteins into structures required for division, is discussed.
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  • 162
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    Journal of Cellular Physiology 98 (1979) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 163
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    Journal of Cellular Physiology 98 (1979), S. 11-16 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: PGE1 elicited a slow, dose-dependent membrane depolarization with an increase in membrane conductance in the somatic cell hybrid TCX11. The ED 50 was 1-2 × 10-8 M with maximal responses at 1-5 × 10-7 M. Dopamine (DA) reversed the effect of PGE1 and caused the membrane potential and resistance to return to control levels. Chronic exposure of cells (measured in minutes) to DA alone would not cause this hyperpolarization. 5-HT was also tested and failed to consistently reverse the PGE1 effects. Chlorpromazine antagonized the effects of DA on the PGE1 response. The electrophysiological results reported here using TCX11 cells are discussed in light of previously reported biochemical results describing interactions of PGE1 and DA, and the electrophysiological effects of DA alone.
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  • 164
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    Journal of Cellular Physiology 98 (1979), S. 17-30 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mutants temperature-sensitive for growth have been isolated from the established line of Chinese hamster fibroblasts Wg1A. These mutants, together with the ones previously isolated by Roscoe et al. ('73), have been characterized with regard to their cell cycle properties. Most of them become arrested in the G1 phase of the cell cycle when incubated under restrictive conditions. By performing temperature shift experiments with synchronous cultures, the execution steps of most of the mutated functions have been located within the second half of the G1 phase.
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  • 165
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    Journal of Cellular Physiology 98 (1979), S. 31-39 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Total cellular calcium levels do not change when 3T3-4a cells stop proliferating due to serum depletion, or when serum-arrested quiescent cells are incubated for up to 44 hours in calcium-deficient medium (∼10 μM Ca++). Upon stimulation with dialyzed serum cells enter S and progress through at least one cycle even at extremely low calcium levels in the culture medium (≥10 μM). Cells divide until a final cell density is attained which is proportional to the calcium concentration in the medium and cells reversibly arrest in G1. Cells which arrested in G1 in medium containing ≤26 μM Ca++ in the presence of excess serum can be stimulated to enter S in response to added calcium after a prereplicative phase of 14 to 16 hours. Serum does not affect 45Ca-uptake in these cells. Benzo[a]pyrene transformed 3T3 (BP3T3) cells have a 100-200 times lower Ca++-requirement than 3T3 cells but arrest in G1 at low Ca++ levels. In contrast, SV40-virus transformed 3T3 (SV3T3) cells that grow without restriction in monolayer cultures have even lower Ca++-requirements for growth than BP3T3 cells and have no Ca++-sensitive restriction point. Therefore, 3T3 and BP3T3 cells have retained the capacity to sense intracellular Ca++-pool sizes and to arrest in G1 at subthreshold cellular Ca++-levels.
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  • 166
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: The ribonuclease (RNase) activity associated with the surface of cells (primarily the Vero line of Green monkey kidney) was assayed under conditions where all cells remained viable as members of colonies or monolayers. RNase activity associated with individual clones was revealed as clear zones of hydrolyzed (acid-soluble) RNA against an opaque background of acidprecipitated RNA in an isotonic agarose-yeast RNA overlay. High resolution assays for single- and double-stranded RNase were achieved by measuring the loss in activity of infectious Sindbis virus RNA, and of the antiviral state induced by poly(rI). poly(rC), respectively.Experiments using these assay procedures revealed that virtually all of the RNase activity associated with viable (intact) vertebrate cells in culture was contributed by the serum in the growth medium, and was superficially adsorbed to the cell surface, rendering it relatively easy to remove by extensive washing.A confluent monolayer of 2 × 106 unwashed Vero cells contained the equivalent of 500 ng of pancreatic RNase, representing about 5% of the total activity initially present in the serum of the growth medium. In terms of serum nuclease activity, only 0.45 ng equivalents of pancreatic RNase in 500 μl were required to destroy 50% of the activity of an infectious Sindbis virus RNA preparation in 15 minutes at 37°C.Cells grown in the absence of serum and cells washed about ten times had comparably low levels of RNase activity-about 100-fold less than unwashed cells grown in the presence of 6% calf serum.The isotonic yeast RNA:agarose overlay procedure may be useful to identify and isolate cell mutants with different endogenous levels, or binding capacities, of surface RNase activity.Operationally, these studies describe the assay of cell surface-associated RNase activity under conditions where all cells remain viable as members of individual colonies or monolayer populations. Specifically, the assay measures the solubilization of yeast RNA in an isotonic agarose mixture overlaying the cells. We describe its use to determine how much of the total RNase activity in viable cell monolayers or colonies is contributed by serum in the growth medium. In addition, we describe the results of two biological assays used as higher resolution probes for cell surface ribonuclease activity: (i) single-strand (ss) RNA, in the form of infectious RNA from Sindbis virus, and (ii) double-stranded(ds)-RNA, in the form of poly(rI). poly(rC) as an inducer of an interferon-mediated antiviral state.
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  • 167
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    Journal of Cellular Physiology 100 (1979), S. 365-374 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Epidermal growth factor (EGF) at nanomolar concentrations stimulated DNA synthesis in confluent, serum-starved cultures of calf aorta and human uterine smooth muscle cells. Stimulation of DNA synthesis in lens epithelial cells was studied for comparison. L and D-ascorbic acid potentiated the effect of serum and EGF on DNA synthesis in calf aorta cells. In contrast L-ascorbic acid had minimal potentiating effect with serum and no effect with EFG present along with serum on DNA synthesis in human uterine smooth muscle and rabbit lens epithelial cells. EGF and ascorbic acid increased cell number when added to stationary phase cultures. Specific binding of 125I-labelled EGF to smooth muscle cells was demonstrated. Receptor concentration in calf-aorta smooth muscle cells was higher in dense cultures compared to sparse cultures. The time course of binding and dissociation of 125I-labelled EGF was similar in “dense” and “sparse” cultures.Human uterine smooth muscle cells in culture exhibited a finite lifespan. There was no stimulation of DNA synthesis in response to serum and EGF in cells of high population doubling level (PDL); although 125I-labeled EGF binding was higher in old cells (high PDL) compared to young cells (low PDL). This increase in binding was shown to be due to changes in the concentration of receptors without changes in their affinity for EGF.
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  • 168
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    Journal of Cellular Physiology 100 (1979), S. 375-382 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of estrogen stimulation in vitro on the electrical properties of vascular smooth muscle (VSM), and the concentration of estrogen receptors in VSM were measured in isolated coronary arteries. Microelectrode measurements of the dog coronary artery membrane potential (Em) showed quiescent values of -51 millivolts (mV) and an input resistance (rin) of 10 megohms. Addition of diethylstibestrol (DES) at 10-6 M hyperpolarized the membrane to -64 mV and reduced in resistance (rin) to 5 megohms within 15 minutes. Extrapolation of the Em vs. log [K]o curve to zero potential gave similar values of [K]i of around 170 mM in both normal and DES treated muscles suggesting that the DES induced hyperpolarization is not due to increased Na-K pump activity. The 0.5% ethanol vehicle alone had no effect on the membrane potentials. Tetraethylammonium ion (TEA) induced action potentials in the previously quiescent tissue. When DES was applied in the presence of TEA, the membrane potential increased and the action potential were abolished. Scatchard analysis of the estrogen receptor binding demonstrated both a high and a low affinity receptor for estrogen in the VSM. These data indicate that DES hyperpolarizes the VSM cells by a mechanism other than an increased Na-K pump activity. The mechanism of this increased Em may be due to factors which increase K+ conductance either mediated directly through estrogen interaction with its cytosolic receptors or through some unidentified second mechanism.
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  • 169
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    Journal of Cellular Physiology 100 (1979), S. 383-387 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relationship of cell surface changes to proliferative decline of human diploid fibroblasts was investigated using the concanavalin A-mediated red blood cell adsorption assay. The amount of the red blood cells adsorbed to human diploid fibroblasts via concanavalin A increased continously from the early phases of cell passage up through cell senescence, while the amount of 3H-concanavalin A binding did not change to a significant extent. The red blood cell adsorption is not a function of cell cycle phase and time spent in culture. Cocultivation of young cells with old cells also did not affect the adsorption capacity of respective cells. Thus, the concanavalin A-mediated red blood cell adsorption can be expected to serve as a new cell surface marker for aging in vitro. Using this marker, it was revealed that transient cell size or 3H-thymidine incorporating capacity do not have a direct relationship with the division age of a cell. Small rapidly dividing cells in old populations resemble large slowly dividing or nondividing cells of the same populations and differ from small rapidly dividing cells in young populations, in terms of cell surface properties.
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  • 170
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    Journal of Cellular Physiology 100 (1979), S. 389-390 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 171
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    Journal of Cellular Physiology 100 (1979) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 172
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    Journal of Cellular Physiology 100 (1979), S. 391-399 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Normal rat hepatocytes have been fused with highly differentiated rat hepatoma cells. Some of the hybrids express a physiologically significant level of activity of the urea cycle enzyme ornithine carbamoyltransferase (OCT), a liver-specific function not found in the hepatoma cells. These hybrids have 10% of the adult rat liver OCT specific activity, incorporate 3H-ornithine into protein arginine, and can be selectively grown in arginine-free medium supplemented with ornithine. Somatic cell hybridization of normal differentiated cells with highly differentiated neoplastic cells of the same tissue type may be useful as a general method for obtaining permanent cell lines with new tissue-specific phenotypes.
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  • 173
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    Journal of Cellular Physiology 100 (1979), S. 407-411 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This report strongly suggests that two compartments in Tetrahymena thermophila contain peptidase activity: the cytoplasm and the outer cell surface.Determinations of amino acid concentrations in the extracellular medium upon incubation of cells with peptides suggest that the surface-bound peptidase activity hydrolyses di- and tri-phenylalanine equally fast on a molar basis.Growth experiments designed to characterize the in vivo peptidase specificities showed that both T. thermophila and T. pyriformis can use L-leucyl-L-leucine, but not L-leucyl-D-leucine as a leucine donor. These results are independent of whether the cells form food vacuoles or not.
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  • 174
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    Journal of Cellular Physiology 100 (1979), S. 413-424 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Stimulation of Balb/c-3T3 cell growth by TPA requires factors found in serum. We examined the interaction between TPA and serum growth factors in the stimulation of cell growth. The number of cells synthesizing DNA (incorporating 3H-thymidine) within 24 to 30 hours after the addition of TPA and the growth factors to density-inhibited Balb/c-3T3 cultures in serum-free medium was determined by autoradiography. With no additions or with TPA (30-300 ng/ml) alone, only 3-7% of cells synthesized DNA. However, TPA synergistically promoted DNA synthesis in combination with each of the defined serum growth fractions, platelet derived growth factor and platelet poor plasma. TPA also synergistically promoted DNA synthesis in combination with purified growth factors including fibroblast growth factor, insulin (10-6-10-5 M), and epidermal growth factor. In all conditions, TPA enhancement of DNA synthesis also resulted in an increase in cell number. Because TPA synergistically enhanced the activity of each growth factor tested, it did not act identically to any of the growth factors.
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  • 175
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    Notes: Prostaglandin generation by human peripheral blood mononuclear cells is enhanced during co-culture with human thyroid cells. The objective of the present study was to determine the influence of various sera on this process.Human thyroid adenoma cell monolayers were cultured with normal human peripheral blood mononuclear cells for three days in the presence of a variety of sera, or serum fractions. Prostaglandin E (PGE) in the medium was measured by bioassay or by radioimmunoassay. Significantly more PGE was generated in cultures containing fetal calf serum than in those containing human serum. This difference was not abolished by dialysis of the human serum. When the 50% (NH4) 2SO4 precipitate of the serum was used, PGE generation was similar to that in fetal calf serum, indicating the presence of an inhibitory factor in human serum. The degree of this inhibitory activity was similar in autologous and heterologous human serum, as well as in normal subjects and patients with Graves' disease. Gel filtration and ion-exchange chomatography of human serum showed the inhibitor to co-migrate with albumin. Evidence presented suggests that the inhibitor is not albumin itself but is, instead, a factor tightly bound to albumin. Inhibitory activity was also found in rabbit, goat, rat and cow serum.Prostaglandins are potent modulators of immune-cell function. These data indicate that this process may be modulated by a factor in mammalian serum. The relative absence of this factor in fetal serum may have important implications in regard to the profound changes which occur in the immune system after birth.
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  • 176
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    Notes: The incubation of human leukocytes with ascorbic acid increased chemotaxis of the cells. In addition, ascorbic acid promoted the assembly of intracellular polymorphonuclear leukocyte (PMN) microtubules as assessed by transmission electron microscopy. Prior incubation of the PMN with colchicine blocked the effect of ascorbic acid on promoting microtubule assembly. Not only did ascorbic acid promote the assembly of microtubules in vivo, but it enhanced the assembly of bovine brain tubulin into microtubules in vitro as quantitated by a glass-fiber filtration assay and by promotion of viscosity changes. The enhancement in leukocyte mobility by ascorbate at concentrations achievable in normal tissues correlates with its ability to assemble microtubule organelles.
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  • 177
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    Journal of Cellular Physiology 100 (1979), S. 139-146 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Benzo[a]pyrene-transformed Balb 3T3 cells (BP3T3) exhibit “normal” growth controls at low concentrations of serum. Epidermal growth factor (EGF) stimulates DNA synthesis and cell division in both Balb 3T3 and BP3T3 cells at physiological concentrations. The growth response of BP3T3 cells to EGF is qualitatively the same as that of 3T3 cells, however, the transformed cells have a lower quantitative requirement. Both 3T3 and BP3T3 cells show a density-dependent response to EGF, but the shift in the dose response curve for BP3T3 cells at high cell density is smaller than that seen for 3T3 cells. One cause of the restricted growth of 3T3 cells at high cell density compared with BP3T3 cells in the increased concentration of growth factor needed for stimulation of 3T3 cells at higher cell densities. A lower rate of depletion of other growth factory by BP3T3 cells may also explain the smaller effect of cell density on the EGF response of these cells.
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  • 178
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    Journal of Cellular Physiology 98 (1979), S. 177-184 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The epithelial cell line, H4-II-E derived from Reuber hepatoma H35 has no significant activity of ornithine carbamoyltransferase (OCT, EC 2.1.3.3) and is not able to grow in arginine-deprived medium.A multi-step selection procedure is described which selects from H4-II-E populations, cells with OCT activity which can grow in arginine-deficient, ornithine-supplemented media.
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  • 179
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    Journal of Cellular Physiology 98 (1979), S. 167-175 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a myeloid leukemia cell line, the inducibilities of the Fc receptor, phagocytosis and cell motility were compared. Thymidine analogues such as BUdR, BCdR and IUdR blocked the induction of phagocytosis and motility but not induction of the Fc receptor. This BUdR susceptibility in the induction of phagocytosis and motility was lost in a BUdR resistant line which was isolated for its growth capability in a high concentration of BUdR. Actinomycin D and puromycin brought about a marked decrease in the inducibility of phagocytosis but not in that of the Fc receptor.This led us to the following conclusion: There is a genetic control in the inducibility of phagocytosis and motility in this cell line, and the incorporation of BUdR into cellular DNA results in the DNA becoming unresponsive to a differentiation-stimulating factor. In contrast, gene activation does not seem to be necessary for induction of the Fc receptor.The order of induction of several differentiation markers was also discussed.
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  • 180
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    Journal of Cellular Physiology 100 (1979), S. 147-157 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Incorporation of (14C)choline and (3H)myo-inositol into the total lipid fraction, incorporation of (14C)acetate into the sterol fraction and incorporation of (3H)thymidine into DNA were studied in human lymphocyte cultures. Concanavalin A induced an increase in the incorporation of these labels with the following features: (a) Phospholipid synthesis was increased promptly. The lag time for the increase in sterol synthesis and DNA synthesis were 5 hours and 27 hours respectively; (b) The increase in phospholipid synthesis and sterol synthesis was proportional to ConA concentration initially. Cells treated with a high concentration of ConA showed very low levels of DNA synthesis; (c) The increase in phospholipid synthesis could be abolished immediately by α-Methyl-Mannoside. α-Methyl-Mannoside blunted but did not abolish the increase in sterol synthesis. α-Methyl-Mannoside enhanced DNA synthesis of those cells which had been treated by a high concentration of ConA; and (d) Selective inhibition of sterol synthesis with 25-hydroxycholesterol did not prevent the increase in phospholipid synthesis, but it blocked the increase in DNA synthesis. Supplement of LDL, HDL or total lipoproteins to lymphocyte cultures was effective in preventing the inhibition of DNA synthesis by 25-hydroxycholesterol. These results suggest that in lymphocyte activation by ConA phospholipid synthesis, sterol synthesis and DNA synthesis were sequentially increased. The rate of cellular commitment to mitogenesis was proportional to ConA concentrations. High concentrations of ConA arrested the cell growth at a postcommitment point in the G1 phase. Enhanced phospholipid synthesis was a precommitment event. Enhanced sterol synthesis was a postcommitment event and reflected the requirement of an increased cholesterol supply for the passage of cell growth through G1.
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  • 181
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  • 182
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    Journal of Cellular Physiology 100 (1979), S. 175-185 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Iodinated proteins were degraded after injection into HeLa cells at first-order rates with half-lives varying from three hours for the trout nonhistone chromosomal protein, HMG-T, to 60 hours for whale myoglobin. Fluoresceinated-bovine serum albumin (fl-BSA) was degraded almost twice as fast as unmodified BSA. The rate of degradation of 125I-BSA was very similar in eight cell lines of mouse, human, monkey and rat origin. Microinjected proteins were analyzed on SDS-acrylamide gels after injection, and for BSA and immunoglobin G, all remaining intracellular 125I migrated at the molecular weight of the injected proteins. By contrast, more than 80% of the extracellular 125I chromatographed as iodotyrosine. With the exception of fl-BSA, which exhibited perinuclear accumulation in approximately one-half of the injected cells, autoradiography showed that throughout the period of study the injected proteins remained dispersed in the cytoplasm.
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  • 183
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    Notes: Cell division in fertilized sea urchin eggs was reversibly inhibited when the ketoaldehyde phenyl glyoxal (PG) at a concentration of 0.1 mM was added to eggs for ten minutes prior to the formation of the mitotic spindle. We investigated whether inhibition of mitosis was due to PG binding to the cell surface (as previously suggested by Stein and Berestecky, '74) or to some intracellular effect. When 14C-PG was added to eggs, label was readily taken up into the egg cytoplasm; very little label was associated with the egg surface. In the cytoplasm PG combined with equimolar amounts of reduced glutathione (GSH), decreasing the levels of cellular GSH to less than 15% of normal and accounting for at least 50% of the PG taken up by eggs. The concentrations of oxidized and protein-bound glutathione were unaffected by PG treatment. We showed that glyoxalase enzymes were present in sea urchin eggs and were capable of metabolizing the PG-GSH complex, thereby restoring GSH to normal levels after PG was removed from the sea water. Though some other effect of PG cannot be ruled out, the major fate of PG in eggs was to combine with GSH, and the transient decrease in GSH which resulted could lead to inhibition of mitosis. While other reports (Nath and Rebhun, '76; Oliver et al., '76) have shown that reagents which oxidize GSH disrupt microtubule-related events, our results showed that such inhibition could be caused by decreased GSH levels alone.
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  • 184
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    Journal of Cellular Physiology 100 (1979), S. 497-507 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A rapid reduction of cyclic nucleotide phosphodiesterase activity occurs after the replating of confluent cultures of BHK 21 c/13 fibroblasts into fresh medium. This reduction in activity depends on the density to which the cultures are reseeded and the concentration of serum in the medium. Enzyme activity in BHK cells is restored after 24 to 48 hours if cells are diluted into medium containing 10% fetal calf serum or 0.5% fetal calf serum supplemented with insulin (10-6 M), but not into 0.5% serum alone. The restoration in enzyme activity is blocked by cycloheximide or Actinomycin D.When BHK cells become quiescent by maintenance in 0.5% serum conditions for 48 hours, a rapid (15-60 minutes) increase in cyclic AMP phosphodiesterase activity occurs when 10% serum is added to the cultures. Enzyme activity is increased even further after 24 to 48 hours in the 10% serum. Cycloheximide or Actinomycin D do not affect the rapid increase in enzyme activity in response to serum, but completely inhibit the long term increase. In contrast to serum, insulin (10-8 to 10-6 M) has no short term effect, but does increase enzyme activity after 24 to 48 hours to levels comparable to those seen with addition of 10% serum. As is the case with serum, this long term effect of insulin on enzyme activity is prevented by inhibitors of protein and RNA synthesis.Kinetic analyses of cyclic AMP phosphodiesterase activity in homogenates of quiescent BHK cells indicate the presence of only high Km (≃ 20 μM) enzyme activity. Addition of serum or insulin to quiescent cells results in the appearance of apparent low Km enzyme activity in homogenates. Sucrose gradient analysis of BHK cells displays two forms of cyclic AMP phosphodiesterase enzyme activity: a 3-4 S form and 5-6 S form. In quiescent cells, the 5-6 form greatly predominates relative to the 3-4 form. Addition of serum to quiescent cells results in a rapid appearance of increased 3-4 S form enzyme activity. Insulin also increases the activity of this higher affinity 3-4 S enzyme form after 24 to 48 hours in culture. The functional significance of short and long term regulation of cyclic nucleotide phosphodiesterase(s) in cells is discussed.
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  • 185
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    Journal of Cellular Physiology 100 (1979), S. 509-518 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The three xanthine derivatives, caffeine, theophylline and 3-isobutyl-1-methyl-xanthine (IBMX) produced dose-dependent increases in cyclic AMP concentrations in HeLa cells after long term treatment. Only IBMX produced increases over the first 60 minutes, with a peak of approximately 5-fold control values five to 10 minutes after the addition of the drug. About four hours after the addition of either 0.67 or 1.0 mM IBMX there was a second peak in the concentration of cyclic AMP which was at least as large and usually larger than the peak observed at five to ten minutes. Neither caffeine nor theophylline increased cyclic AMP concentrations above control values until one hour after addition of the compounds, and there was no indication of a peak in the concentration at four hours. Between 24 and 72 hours, all three compounds produced elevations in cyclic AMP levels that were steadily maintained. At any given concentration, the order of potency was IBMX 〉 theophylline 〉 caffeine. If the xanthine derivatives were removed from the medium after 24 hours of treatment, the cyclic AMP concentrations fell to control levels within one hour. Treatment with 5-iodo-2′-deoxyuridine (IdUrd) or hydrocortisone alone did not change the levels of cyclic AMP, nor did the presence of these inducers of alkaline phosphatase activity alter the effects of the xanthine derivations on cyclic AMP concentrations. The data showed a significant correlation between the magnitude of the increase in cyclic AMP concentrations over the period from 24 to 72 hours and the degree of inhibition by the xanthine derivatives of the induction of alkaline phosphatase activity.
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  • 186
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    Journal of Cellular Physiology 100 (1979), S. 539-550 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Binding of Concanavalin A to mouse L cells which were grown in serum free, chemically defined medium and depleted of their membrane sterol by blocking their de novo sterol synthesis was investigated. Kinetic analysis of binding data implied positive cooperativity, with two different affinities for Con A, in both experimental and control cultures. The amount of Con A bound to the cell surface at saturation was approximately 0.5 picomoles per mg cellular protein in controls and approximately 1.0 picomoles per mg cellular protein in 25-hydroxycholesterol treated cultures (which had a reduced sterol concentration of up to 50% in their plasma membranes). This phenomenon was reversed when cholesterol or mevalonate was added to the inhibited cultures to compensate for their inability to synthesize sterol. Our findings indicate that lectin binding to specific glycoprotein receptors is influenced by membrane lipid composition.
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  • 187
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    Journal of Cellular Physiology 100 (1979), S. 519-529 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The interaction of mitogenic factors on a single cell type and the comparative activity of a given factor in diverse cell types have been studied byapplying the principles of Michaelis-Menten kinetics to clonal growth data. Such comparisons are facilitated by derivation of two parameters; Kmmitogen, the mitogen concentration that gives half-maximal clonal growth and a theoretical maximal growth rate, RMAXT. Both parameters are analogous to the Km and VMAX as applied to enzymatic reactions. Use of these parameters permits meaningful comparisons between cells with different growth rates.Using kinetic analysis of dose-response data, we found that normal human epithelial cells require 200 times more fetal bovine serum protein (FBSP) than a malignant line to multiply at their respective half-maximal rates. Further, the KmFBSP of normal cells was reduced to that of the malignant line by the inclusion of growth factors (EGF or FGF, and hydrocortisone) in the medium. On the other hand, even though greater levels of serum were required when growth factors and hydrocortisone were not present, their inclusion did not alter RMAXT. Interactions between mitogenic factors were shown to be unidirectional. Although EGF reduced the KmFBSP, FBSP did not change the KmEGF. The same type of analysis revealed that hydrocortisone, which potentiated the mitogenic activity of EGF did not change the KmEGF. Kinetic analysis of cell growth should prove useful in studies on the relation between growth and tumor promotion as well as in the evaluation of growth-inhibiting chemotherapeutic agents.
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  • 188
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    Notes: Subcellular organelles from livers of rats three days prenatal to 50 weeks postnatal were separated on sucrose gradients. The peroxisomes had a constant density of 1.243 g/ml throughout the life of the animal. The density of the mitochondria changed from about 1.236 g/ml at birth to a constant value of 1.200 g/ml after two weeks.The peroxisomal and mitochondrial fatty acid β-oxidation and the peroxisomal and supernatant activities of catalase and glycerol-3-phosphate dehydrogenase were measured at each age, as well as the peroxisomal core enzyme, urate oxidase, and the mitochondrial matrix enzyme, glutamate dehydrogenase. All of these activities were very low or undetectable before birth. Mitochondrial glutamate dehydrogenase and peroxisomal urate oxidase reached maximal activities per g of liver at two and five weeks of age, respectively.Fatty acid β-oxidation in both peroxisomes and mitochondria and peroxisomal glycerol-3-phosphate dehydrogenase exhibited maximum activities per g of liver between one and two weeks of age before weaning and then decreased to steady state levels in the adult. Peroxisomal β-oxidation accounted for at least 10% of the total β-oxidation activity in the young rat liver, but became 30% of the total in the liver of the adult female and 20% in the adult male due to a decrease in mitochondrial β-oxidation after two weeks of age. The greatest change in β-oxidation was in the mitochondrial fraction rather than in the peroxisomes. At two weeks of age, four times as much β-oxidation activity was in the mitochondria as in the peroxisomal fraction. Peroxisomal glycerol-3-phosphate dehydrogenase activity accounted for 5% to 7% of the total activity in animals younger than one week, but only 1% to 2% in animals older than one week.Up to three weeks of age, 85% to 90% of the liver catalase was recovered in the peroxisomes. The activity of peroxisomal catalase per g of rat liver remained constant after three weeks of age, but the total activity of catalase further increased 2.5- to 3-fold, and all of the increased activity was in the supernatant fraction.
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  • 189
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    Journal of Cellular Physiology 101 (1979), S. 399-405 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cultures of heat-synchronized Tetrahymena pyriformis, growing in a proteose peptone medium, were subjected to short pulses of the amino acid analogue, p-flurophenylalanine, and high hydrostatic pressure. The pulses of these agents were chosen so that, when applied individually, they did not appreciably delay cell division. However, combined treatments, analogue pulse followed by pressure pulse, produced a pronounced synergism. The results are interpreted as further evidence to support the inclusion of analogue division proteins in pressure labile assemblies during the progression of Tetrahymena into division.
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  • 190
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    Journal of Cellular Physiology 101 (1979), S. 407-417 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When replicating DNA is labeled sequentially with radioactive and density tracers and analyzed by equilibrium centrifugation, the fraction banding at heavier than normal density is inversely proportional to the rate of replication fork movement if there is a sharp transition from one tracer to the other on the newly synthesized chains (Painter and Schaefer, '69). Primate CV-1 DNA labeled for 5 to 30 minutes with 3H-dThd and then for three hours with BrdUrd in the presence of FdUrd bands in a bimodal distribution in alkaline CsCl, rather than in a continuous distribution with a skew toward heavier density seen when FdUrd is omitted and centrifugation is in neutral CsCl. The heavy density peak represents interspersion of both tracers in the DNA and is caused by slow transition from dThd to BrdUrd incorporation when the tracers are switched in the labeling medium. This may result from preferential uptake and incorporation of dThd over BrdUrd. Because of the interspersion, calculation of the rate of replication fork movement is inaccurate. Reversal of the labeling sequence with administration of the long density pulse before the radioactive pulse reduces the problem of interspersion. Using this sequence of labeling, estimates of the rate of fork movement of 0.36-0.38 μm/min are obtained when the 3H pulse time is long enough to allow accurate measurement of the fraction of heavy DNA. Analysis by fiber autoradiography yields a rate of 0.56 μm/min in the same cell line. If appropriate precautions are taken to minimize mixing of the two tracers in the precursor pool and to ensure that the fraction of heavy DNA is measured accurately, the hydrodynamic technique provides an objective method of measuring rate of fork movement that gives values only slightly lower than those obtained by autoradiography.
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  • 191
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    Journal of Cellular Physiology 101 (1979), S. 419-430 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A variant endothelial cell type was found to arise spontaneously from cultures of bovine aortal endothelial cells. This variant showed no contact inhibition and overgrew confluent cultures of wild-type endothelial cells. Unlike other reported variants of this cell type produced by chemical mutagenesis or by withdrawal of polypeptide growth factor, this variant retained the capacity to synthesise factor VIII antigen, but showed no alteration from wild-type in capacity to adsorb platelets. The variant also had an increased capacity to bind FITC-conjugated con A to its surface.
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  • 192
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    Journal of Cellular Physiology 101 (1979), S. 431-438 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Extracts of submaxillary glands from two different strains of inbred mice were mitogenic for human endothelial cells in culture. The mitogenic activity of extracts from glands of males of the SWR/J and C57BL/10J strains were equivalent, and the growth stimulating effect was unrelated to renin or esteroproteolytic activity. Mitogenic activity in extracts from SWR/J females was less than that from males, and extracts from C57BL/10J females were inactive. The polypeptide growth factors, epidermal (EGF) and fibroblast (FGF) growth factors, also stimulated replication of endothelial cells. Cells from either umbilical arteries or veins responded to submaxillary extracts, EGF, or FGF with a similar increase in cell number, increase in protein and enhanced uptake of 3H-thymidine. The proliferative response was associated with decreased activity of angiotensin I converting enzyme which is localized on the endothelial surface. Nerve growth factor (NGF) was not mitogenic for endothelial cells. Extracts of submaxillary glands from male mice of either strain contained approximately 20 times more EGF than extracts from females, as determined by immunodiffusion. Mitogenic activity of the extracts was completely inhibited by antiserum to EGF, suggesting that the active component of these preparations is EGF.
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  • 193
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    Journal of Cellular Physiology 101 (1979), S. 439-457 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Leupeptin, chymostatin and antipain inhibited the degradation of long-lived proteins in cultured rat hepatocytes by 20-30%, probably by inhibiting lysosomal proteases:(1) Leupeptin and chymostatin decreased to a similar extent the degradation of an exogenous protein 125I-asialo fetuin, a process known to occur within lysosomes. (2) In extracts of cells treated with leupeptin, cathepsin B activity was inhibited by 35-50%. (3) Leupeptin, chymostatin and antipain inhibited proteolysis by homogenates of liver lysosomes but not by the supernatant fraction. These agents, however, do not appear to rapidly permeate the membrane of isolated lysosomes.Leupeptin, chymostatin and antipain did not inhibit the breakdown of short-lived normal cell proteins, and ones containing amino acid analogs. Even when the amount of abnormal proteins was increased, such that it comprised a large fraction of cell protein, the degradation of these polypeptides was still very rapid and not affected by these inhibitors. The pathway for the degradation of short-lived cell proteins thus appears distinct from that responsible for degradation of long-lived cell proteins. In accord with this conclusion, reduction of the temperature of cultures inhibited the breakdown of long-lived proteins to a much greater extent than it affected the breakdown of short-lived ones.Treatment of cultured hepatocytes with glucagon, or deprivation for serum or amino acids stimulated the degradation of the more stable cell proteins but did not affect the breakdown of 125I-asialo-fetuin. Under these conditions leupeptin and chymostatin inhibited the breakdown of long-lived cell proteins to the same extent as in control cultures. Thus, lysosomal enzymes seem to play an important role in protein breakdown both in fed hepatocytes and in cells where proteolysis is accelerated.
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  • 194
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    Journal of Cellular Physiology 98 (1979), S. 315-326 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The temperature sensitive leucyl-tRNA synthetase mutant tsHl and two revertants have been compared to the parental Chinese hamster ovary cells with respect to the effects of amino acid concentrations in the medium on growth. Elevating the leucine concentration 30- or 100-fold allowed tsHl to grow exponentially at 38.5°C, normally the nonpermissive temperature. Partial revertants that had recovered some enzyme activity required smaller supplements for growth. Measurements of the leucine pools indicated that they respond directly to the extracellular leucine concentration and may mediate the effect. Use of combinations of amino acids confirmed that isoleucine has a similar though weaker effect on tsHl and identified an even weaker protection by valine. The triple combination of leucine, isoleucine and valine was a much more efficient medium supplement and three times normal concentrations of these amino acids supported growth of tsHl at 38.5°C. It is postulated that they are acting at their respective aminoacyl-tRNA synthetases to help stabilize a complex which also contains the mutant leucyl-tRNA synthetase. The pool size measurements also showed that the leucine pools of tsHl and a revertant increased 2-fold more in a response to increased temperature than those of WT. It is suggested that this is a regulatory response to low leucyl-tRNA synthetase activity and is important in determining growth phenotypes.
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  • 195
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    Journal of Cellular Physiology 98 (1979), S. 327-339 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Nine spontaneous and seven ethyl methanesulfonate induced revertants of the Chinese hamster ovary cell line mutant (tsHl), which possesses a temperature sensitive leucyl-tRNA synthetase, were isolated and characterized with respect to growth rate, leucyl-tRNA synthetase activity and thermolability, intracellular leucine pool size, and rRNA content. Although most revertants had increased leucyl-tRNA synthetase activity, and of those tested, all but one had increased thermostability, each appears to be unique. One revertant may be an intergenic suppressor since it appears to contain an elevated level of tsHl-like synthetase. There was no evidence for any of the revertants having increased rRNA and tRNA contents, however, many showed leucine pools two to three times larger than wild type cells. Since similar increases have been observed in tsHl cells they are believed to result from regulation of leucine pool size by the leucyl-tRNA synthetase and are of a magnitude sufficient to affect significantly the growth of revertants at 38.5°C.
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  • 196
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    Journal of Cellular Physiology 98 (1979), S. 371-376 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Freshly explanted human myeloma cells formed colonies of monoclonal plasma cells in soft agar in the presence of medium conditioned by the adherent spleen cells of mineral oil-primed BALB/c mice. The medium showed peak activity at a dilution of 1:4. 2-mercaptoethanol or monothioglycerol was necessary for colony formation. Other thiols tested were ineffective in promoting colony growth. Colony-forming cells adhered to nylon wool, but not glass beads or plastic dishes. The presence of E-rosetting cells was not required for myeloma colony formation. Antibody prepared against a human myeloma cell line, RPMI 8226, reduced colony formation. These studies demonstrate the usefulness of this bioassay for determining functional properties of the myeloma colony-forming cell.
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  • 197
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fibroblasts were isolated from keloid, normal skin, and normal scar and maintained in tissue culture for four passages. Growth kinetics were the same for all groups on days 2 through 12. However, the rate of collagen synthesis per fibroblast was greater in keloid derived cells than any controls at all growth phases. Keloid fibroblasts have an autonomous capacity to synthesize collagen at a significantly increased level in vitro, which may explain in part why these lesions are characterized by increased collagen deposition.
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  • 198
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    Journal of Cellular Physiology 100 (1979), S. 551-561 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cation loss and hemolysis of various mammalian red cells suspended in isotonic non-electrolyte media were investigated. Sucrose buffered with 10 mM Tris-Hepes, pH 7.4 was used as the non-permeable non-electrolyte. Mammals from which the red cells were derived include the human, guinea pig, rat, rabbit, newborn calf, newborn piglet and pig, all of which contain K as the predominant cation species (HK type) and the dog, cat, sheep and cow, all of which possess Na as the predominant cation species (LK type). Of HK cells, a rapid efflux of K takes place from humans, rats and guinea pigs. Of LK type cells, the dog and cat exhibit an augmented membrane permeability to Na. The governing factors which influence cation permeability are the change in pH, temperature, and ionic strength. In response to increase in pH, the red cells of humans, dogs and cats become more permeable to cations, whereas the red cells of rat and rabbit are unaffected. In response to increase in temperature, HK type cells exhibit augmented K efflux, while the Na loss from the dog and cat cells manifest a well-defined maximum at near 37°C. In all cases, a small substitution of sucrose by an equal number of osmoles of salts results in a dramatic decrease in cation loss. By contrast, the red cells of the rabbit, newborn calf, adult cow, newborn piglet, adult pig and sheep display no discernible increase in ion-permeability under the conditions alluded to above. In some species including the newborn calf, dog and cat, an extensive hemolysis occurs usually within an hour in isotonic buffered sucrose solution. The osmolarity of sucrose solution affects these cells differently in that as the osmolarity increases from 200-500 mM, hemolytic rates of the calf and dog reach a saturation near 300 mM sucrose, whereas the hemolytic rate of the cat decreases progressively. Common features pertaining to this hemolysis are (1) the intracellular alkalinization process; and (2) the diminution of the cell volume which take place prior to and onset of hemolysis. SITS, a potent anion transport inhibitor, completely protects the cells from hemolysis by inhibiting chloride flux and the concomitant rise in intracellular pH.
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  • 199
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    Journal of Cellular Physiology 101 (1979) 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 200
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    Journal of Cellular Physiology 100 (1979), S. 589-601 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Rous-sarcoma transformed BHK cells can be continuously cultured in a medium containing Eagle's Minimal Essential Medium, iron and biotin. The rate of cell multiplication increased when serine, or serine plus other non-essential amino-acids were added to the medium. With biotin deleted from the medium there is a reduction in DNA synthesis and most cells are blocked in G1.
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