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  • ASTROPHYSICS
  • Cell & Developmental Biology
  • 1980-1984
  • 1965-1969  (573)
  • 1925-1929
  • 1967  (184)
  • 1966  (207)
  • 1965  (182)
Collection
Publisher
Years
  • 1980-1984
  • 1965-1969  (573)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 549-563 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Visualization of stainable material in the neural lobe of the rat provided the most reliable index of the age at which secretory activity can first be recognized, though preceded by both hypothalamic synthesis and axonal transportation. A problem of interpretation was encountered in the neural lobes of fetal and infant animals, due to different staining responses obtained during this age period, to the two methods of staining employed; chrome alum hematoxylin-phloxin and aldehyde fuchsin after oxidation by either acidified potassium permanganate or performic acid. With aldehyde fuchsin the material of the neural lobe is stainable selectively from the eighteenth day of fetal life to adulthood. With hematoxylin phloxine the first staining response also occurred in the posterior lobe but much later, at the end of the first postnatal week.The staining situation in the pars neuralis has its counterpart in the differentiating hypothalamic nuclei; complicated by the differentiation of the supraoptic nuclei some days in advance of the paraventricular nuclei. After aldehyde fuchsin staining, evidences of neurosecretory activity were present in the perikarya of the supraoptic nuclei at birth, but mature neurons were rarely seen in the paraventricularis until at least 24 hours later. Nuclei of fetal hypothalami were not studied, but the demonstration of stainable material in the fetal neural lobes constitutes circumstantial evidence of functional competence of some neurons of either one or both types of nucleus, most likely the supraoptic.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 1-5 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Small crenulated erythrocytes appear in the circulation of Rana pipiens during metamorphosis, increases in number as metamorphosis proceeds and gradually lose their wrinkled appearance. At the end of metamorphosis the entire red cell population has been replaced by these new cells. Thyroxine induces the premature appearance of these new cells in young tadpoles.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 39-50 
    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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  • 4
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution and morphology of the argentaffin cell population within the stomach of the albino rat has been investigated histologically. The argentaffin cell's situation is restricted to and evenly distributed over the antrum, lying usually in the basal third of the mucosa among mucous cells. A band of mucosa, less than a millimeter wide, containing argentaffin cells, extends from the antrum and encircles the stomach just caudal to the forestomach. The argentaffin cell population is found in less than three-tenths of the total stomach by weight, a point for consideration in serotonin assay.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966) 
    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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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 89-100 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This report presents a study of cataracts seen in a random-bred strain of Swiss mice with Balb/c mice used as a control group. The embryonic development, and histological and slit lamp observations of the lenses in the two groups of animals are contrasted.The cataract is dominant in its inheritance (Tissot, '62). It appears either unilaterally or bilaterally as a dense white opacity in the lens substance. The earliest sign of abnormal formation occurs at 14 days of embryonic development. This is associated with a defect in the primary lens fibers formation. Progressive degeneration of these fibers occurs until they are reduced to a mass of cellular debris seen at the last day of gestation. The secondary fibers are also laid down in an abnormal manner. The normal lamellar arrangement of the secondary fibers is not seen in cataractous lenses.The abnormal lens fiber development leads to progressive vacuolization.The mature cataract seen in the adult is filled with many vacuoles, the largest ones occurring at the equatorial region. The nuclear region consists of a clumpy eosinophilic mass with scattered calcified areas. The rate of growth of the secondary fibers is different from that of the normal group. Most of the mature cataracts in the adult contain a vascularized epithelium.There are three possible areas of primary involvement which may lead to the development of the cataract. This are: (1) A defect in the development of the primary lens fibers; (2) A defect in the development of the secondary lens fibers; (3) An abnormal lens epithelium which may interfere with nutrition of the lens and thus initiate cataract formation.
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  • 7
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spiroid orientation of the circumferential heart wall muscles is described for Centruroides sculpturatus Ewing. This muscle arrangement accounts for differences in ostial position when the heart of this species is compared to that of Uroctonus mordax Thorell. Other differences, such as number of lateral arteries present, cannot be explained on the basis of circumferential muscle orientation.The histology of the heart and associated vessels, but not the supraneural vessel, was found to be similar in both species. The lateral, posterior, communicating and sternal arteries all possess a muscularis composed of irregularly spaced, apparently branched, striated muscle fibers. External to this is a covering of connective tissue. The lumina of these arteries, the aorta, and the supraneural vessel are lined with a homogeneous, PAS-positive membrane. This membrane is also seen in blood vessels which penetrate the nervous system. It was not observed in vessels accompanying major nerves.Findings are compared to those of other authors. Differences in the structure of the hearts of these two species are discussed in relation to the microanatomy of other arachnid hearts.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 233-240 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and replacement of teeth in the frog Rana temporaria is analyzed by dividing the life cycle of the tooth into a number of stages. These stages are identified by the examination of alizarin whole mounts. The dentition in this species is fairly complete and the percentage of functional loci is approximately 74. The teeth in alternate loci are usually at about the same stage in development. The low percentage of non-functional loci is accounted for by the retention of functional teeth over a large fraction of the total life cycle time and the relatively rapid ankylosis of replacement teeth. It is suggested that tooth replacement is essentially a process which involves teeth in alternate loci and that the replacement waves (which connect alternate loci) run parallel to the longitudinal axis of the jaw and are of infinite length. This basic pattern is obscured by many breaks which occur in the replacement waves. The presence of such breaks may be accounted for by variations in the time intervals between the successive stimuli which initiate the Zahnreihen, or simply by the acceleration or deceleration of the development of teeth in one or more loci.
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  • 9
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The major features of the morphogenesis of the muscles of the hindlimb, exclusive of the foot, are described and illustrated for the frog, Rana pipiens The description is carried through the stage XII larva, in which stage most of the muscles of the adult limb are present in essentially the definitive condition. As is true of other vertebrates which have been studied, the muscles of the hindlimb develop from two major premuscular masses. One of these lies along the dorsolateral margin of the limb and the other along the ventro-medial margin. Each of the two masses is subsequently divided into smaller and smaller subdivisions as the different muscle groups and the individual muscles are differentiated. In general, the more proximally located muscles differentiate before those which are located more distally and those of the dorso-lateral mass before those of the ventro-medial mass.The following muscles of the thigh, shank and tarsus develop from the dorsolateral mass: ileo-fibularis, glutaeus magnus, cruralis, ileo-femoralis, iliacus externus, iliacus internus, tensor fasciae latae, pectineus, adductor longus, peroneus, tibialis anticus brevis, tibialis anticus longus, extensor cruris brevis, tarsalis anticus, extensor digitorum communis longus and abductor brevis dorsalis. The following develop from the ventro-medial mass: compressor cloacae, circumflexor arteriae, pyriformis, semimembranosus, gemellus, gracilis major, gracilis minor, semitendinosus, adductor magnus, obturator internus, obturator externus, quadratus femoris, sartorius, plantaris longus, tibialis posticus, tarsalis posticus, plantaris profundus, intertarsalis and flexor digitorum brevis superficialis.
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  • 10
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tissues of White Leghorn embryos of stages 17-45 and chicks of one day, two days, and three weeks of age were frozen, sectioned in a cryostat and, where appropriate, were fixed in cold calcium formol. Acid phosphatase, non-specific esterase, adenosine triphosphatase, 5-nucleotidase, non-specific glycerophosphatase, nucleotidediphosphatase, and glucose-6-phosphatase were localized in these tissues. Ribonucleic acid, acid mucopolysaccharides, triglycerides, and neutral fats were localized in tissues fixed with FAA and embedded in paraffin.Positive acid phosphatase reactions were obtained in the epithelium of the trachea and esophagus at all stages of development. 5-nucleotidase was found in the muscularis mucosae of the esophagus at all stages. Non-specific esterase appeared with histodifferentiation of the esophageal epithelium. Ribonucleic acid was localized in the basal regions of the epithelium.Mucous glands of the esophagus are rich in ribonucleic acid and acid phosphatase at all stages of development. With histodifferentiation and the onset of secretion of sulfated acid mucopolysaccharides, the glands and their ducts become highly reactive for adenosine triphosphatase and nucleotide-diphosphatase, indicating a role of these enzymes in secretion.
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  • 11
    Electronic Resource
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 119 (1966), S. 277-281 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Testicular structure in bisexual teiid lizards (Cnemidophorus and Ameiva) is apparently unique among vertebrates in having a circumtesticular subtunic band of Leydig (interstitial) cells, that varies in species of Cnemidophorus from 1.2 to 42.1 cells in thickness (transverse cross-section), between the outer tunic (tunica albuginea) and the seminiferous tubules. The regression on body size, ontogenetic change, seasonal periodicity, and other aspects of structure and function of this subtunic Leydig cell structure are discussed.
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  • 12
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The egg chamber of Drosophila melanogaster consists of 16 interconnected cells surrounded by a monolayer of follicle cells. Each 16 cell cluster (from which the oocyte and 15 nurse cells differentiate) arises within the germarial region of an ovariole. To study the ultrastructure of the early stages in the formation and differentiation of egg chambers, a three dimensional reconstruction was made from serial thin sections through a germarium from a 24-hour old, virgin female. The germarium was found to be subdivided into three regions: (1) The mitotically active area where clusters of 16 cells originate from a series of cystocyte divisions, (2) the region where these cells interact with mesodermal cells, and (3) the region where the germarial cyst is transformed into the first egg chamber in the vitellarium. Since cystocytes were found to decrease in size with each division, the possibility exists that cell size may determine when the divisions cease. Models are presented which mimic with varying degrees of success the developmental changes the germarial cells undergo with time. Hypothesis are developed to explain why stem line oogonia are restricted to the anterior portion of the germarium, why mesodermal cells first interact with cystocytes in region 2, and why the oocyte is oriented posteriorly. The nuclear differentiations of the component cells of the chamber are described and correlated with observed differences in radiosensitivity. Symbionts were observed in the germaria of several strains of Drosophila, and the bearing of these findings upon nutritional studies is discussed.
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  • 13
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The physiology and fine structure of the vibration receptor of the spider (Achaearanea tepidariorum) was studied throughout the process of molting. The physiological studies showed that there is no dramatic change in the receptor's vibration sensitivity as the time of ecdysis approaches. Only a gradual loss of sensitivity can be detected on a statistical basis using large numbers of spiders. The fine structural studies suggest that the connection between the sensory neurone and the receptor within the old cuticle remains intact up to the time that the cuticle is shed.
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  • 14
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Since the rabbit's eye more nearly resembles the human eye than any other mammal used in experimental investigations, a detailed study of its ciliary arteries has been made. A closely timed series of embryos injected through the living umbilical vein and rendered transparent show, in thick sections, silhouetted vessels in perspective. Heretofore the ciliary arteries have been studied from their first identification until they have reached the primitive choriocapillaris, but no farther. This study shows their complete history including their relation to the circulus arteriosus iridis major and to the pupillary membrane. Our special concern has been ferreting out the mode of migration of the components of the definitive arteries. New findings include: (1) an arteriovenous plexus which mediates the transference from vessels anastomotic with it to other such vessels; (2) functionally different segments of the primitive ciliary arteries; (3) different arterial and venous plexuses which play roles in embryonic development; (4) discovery of the realignment of the choriocapillaris into vertical vessel meshes with transverse anastomoses between them, each of which have different fates; (5) the mode of development of the circulus arteriosus iridis major; (6) a crown of venous vessels looping around the iris margin; and (7) a special arterial supply for the ciliary processes.
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  • 15
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The phylogenetic development of neuroglia (astrocytes, oligodendrocytes) was investigated in homologous cortical and subcortical forebrain regions of selected vertebrates. Microglia were not considered in the current study.Four to seven brains from each species were used. Scharenberg's modification for astroglia of del Rio Hortega's silver carbonate technique was used. The analysis of neuroglia cells was based on (1) the characteristic cellular morphology found in each species, (2) a comparison of the selected regions in each animal, (3) the interrelationships of astrocytes and their relations to neurons, blood vessels, and oligodendrocytes.The predominant type of neuroglia found in the fish, frog, and lizard was the ependymal cell; however, non-ependymal glial cells were also present. The bird represented a transitional phylogenetic stage from a predominance of ependymal glial to a predominance of non-ependymal glia. A progressive increase in the morphological relationships of glial cell bodies and processes to neurons was found with ascension of the phylogenetic scale from fish through primate.Interrelations were observed between adjacent astrocytic processes and cell bodies, and between astrocytes and oligodendrocytes. The processes of adjacent glial cells also appeared to show an increase in thickness at the point of approximation. A variety of astrocytes were observed ranging from small, round-oval shaped cells to large polygonal or stellate forms. Variations in the number of astrocytic processes, their thickness, and degree of secondary branching were described, and their possible functional significance was discussed.
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  • 16
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gland cells of the gastrodermis of Hydra when isolated from the epidermis are capable of dedifferentiating into interstitial cells. Under proper environmental conditions these interstitial cells are capable of undergoing meiotic divisions and forming normal gametes. This dedifferentiation and redifferentiation sequence has been studied at the level of the light and electron microscope. It is concluded that in Hydra there is no specific germinal cell line determined during embryogeny, and that a somatic cell under proper environmental conditions can be induced to undergo meiosis.
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  • 17
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The rectal epithelium of Calliphora is made up of three quite distinct cell types: rectal, cortical and junctional cells.The thin wall of the rectal pouch is made up of rectal cells which are relatively simple and unspecialized; their general structure does not suggest any direct participation in ion transport.A function of ion and water transport can probably be ascribed to the cortical cells, which are arranged in the form of four cones which project into the rectal lumen. The cavity of each cone is filled up with tracheae, nerve and neurosecretory terminals, and connective tissue to form medulla. The medulla and cortex are separated from each other by deeply staining bridges or trabeculae to form an infundibular space. The most conspicuous feature of the cortex is the presence of an extensive intercellular sinus formed by complex infoldings of the lateral plasma-membranes. It is postulated that fluid, which is absorbed from the rectal lumen, is transported into the intercellular sinus and finally reaches the haemolymph via the infundibular space. The actual site of ion transport is probably the stacks of lateral plasma-membrane which are closely associated with mitochondria.The junctional cells, which are packed with microtubules, form a collar around the base of the papillae at the point of their insertion into the rectal wall.It is suggested that the neurosecretory terminals present in the medulla might release a hormone which controls rate of ion and water reabsorption by the papillae cells.
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  • 18
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The long, filamentous antennal flagellum of Carausius morosus has on it three types of sense organs (1) tactile hairs, (2) thick-walled chemoreceptors and (3) thin-walled chemoreceptors. Tactile hairs and thick-walled chemoreceptors are present on all of the 40 or more flagellar subsegments while thin-walled chemoreceptors are limited to about one-third of them. Thin-walled chemoreceptors are present on subsegments nine and ten, one of the subsegments between 15 and 20 and from approximately the thirtieth subsegment to the distal end of the antenna. A description of each of these sense organs is given. No coeloconic or campaniform sense organs were found.
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  • 19
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoarchitecture of the choroid plexus of the third ventricle and the paraphysis was investigated in some lower vertebrates to compare the histologic characteristics of these organs. Both epithelia are similar in appearance in the same class. Minor microscopic variations exist in the different classes of vertebrates, but do not provide a fundamental distinction between the two organs. The epithelia, moreover, have similar staining properties, contain mucicarmine- and PAS-reactive materials, and are derived from a common neuroepithelium. Tubules are identified in the choroid plexus and in the paraphysis; all are similarly formed by simple folding of epithelium on the surface into the stroma. The paraphyses in all vertebrates studied contain villi similar to those seen in the choroid plexus. Cilia are identified in both choroidal and paraphyseal epithelia, and are not an indication of degree of epithelial differentiation. Many types of epithelium are noted in both organs during histologic differentiation as well as in the mature stage. Functionally, the choroid plexus is active in both secretion and absorption. Accumulation of particulate material within the epithelial cytoplasm may indicate phagocytic as well as absorptive activity of cells. Based on a common neuroepithelial origin and similar histochemical properties, we conclude that the paraphysis is a modified choroid plexus. The velum transversum is an arbitrary boundary between diencephalon and telencephalon, and is itself formed of choroid plexus. The medial telencephalic ventricle is the rostral portion of the third ventricle. All neuroepithelial infoldings at the rostral end of the diencephalic roof including the velum transversum are intraventricular choroid plexuses; the neuroepithelial outpouchings in this region are the extraventricular choroid plexuses (paraphysis) of the diencephalon.
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  • 20
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The left ovary of the bonnethead shark, Sphyrna tiburo, is rudimentary, and the right ovary supplies both oviducts which share a common ostium situated in the falciform ligament. Preceding ovulation the nidamental gland of each oviduct hypertrophies and the caudal two-thirds of each oviduct is modified to form a uterus. In the Florida-Caribbean area Sphyrna tiburo probably mates in March and 3-7 eggs are fertilized in the vicinity of the nidamental gland of each oviduct.The developing embryo is nourished during the first 3-4 months of gestation by yolk stored in its extensive yolk sac. Approximately three and one-half months after fertilization, the distal portion of the yolk sac becomes convoluted and interdigitates with deep folds in the uterine wall to form a yolk-sac placenta. As the placenta develops, the maternal uterine epithelium is reduced from columnar cells to squamous cells, and the foetal yolk-sac epithelium is reduced from columnar and cuboidal cells to squamous cells. Exchange between the maternal and foetal blood systems takes place through maternal endothelium, reduced maternal epithelium, egg-case membrane, reduced foetal epithelium, and foetal endothelium.
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  • 21
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966) 
    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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  • 22
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 120 (1966), S. 347-358 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histochemical methods for mucins were applied to the ovaries of 23 dogs.Solid and hollow groups and cords of epithelial cells (subsurface epithelial structures, SES) in the outer part of the cortex regularly showed evidence of mucin secretion. Intracytoplasmic, sialic acid-containing, acid mucin secretion droplets were seen in solid and hollow SES, and secretion was present in both closed lumina and those opening onto the surface.Intracytoplasmic droplets in the cells of SES were distinctive, and similar droplets were not found in the cells of any other ovarian epithelial component. The secretion of SES was not shown to possess distinctive histochemical features.Mucin production was also observed in follicles, corpora lutea and rete tubules.The significance of ingrowth from the ovarian surface epithelium in adult life, and of secretory activity by the cells of SES, are discussed.
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  • 23
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 121 (1967) 
    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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  • 24
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This is the last of a series of observations involved in a comparative histological study of the ultimobranchial body in vertebrates. Complete serial longitudinal or transverse paraffin sections were made of formol alcohol, Bouin's, and formalin-fixed ultimobranchial and thyroid tissues that had been removed from adult specimens of the cat, cotton rat, ground squirrel, Guinea pig, kangaroo rat, bushytailed wood rat, rabbit, and raccoon. The alcian blue-PAS, aldehyde fuchsin-alcian blue, mucicarmine, alcian blue-safranin, Best's carmine, and toluidine blue staining procedures show that the glandular mammalian ultimobranchial tissue is capable of producing considerable amounts of various mucosubstances, particularly the acid mucopolysaccharides, and other carbohydrate-containing materials. The carbohydrate moiety has been histochemically identified as mucopolysaccharides possessing acidic groups, those having both carboxyl and ester sulfate groups; and as glycogen, muco-and glycoproteins and other carbohydrate-protein complexes. The differences in the intensity and localization of a given staining reaction reflect not only individual and species variations but also significant differences in the position of the ultimobranchial tissue in relation to the thyroid gland. An accessory thyroid lobule found near parathyroid IV and thymus IV in a bushy-tailed wood rat may represent a cystic manifestation of the ultimobranchial body because its follicles varied greatly in size and were lined by a thick stratified squamous epithelium. The possible hormonal mechanisms (TSH, thyroxine) involved in the regulation of ultimobranchial activity are discussed in relation to the gland's production, storage, and release of mucopolysaccharides and other secretory substances.
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  • 25
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An electron microscope study of oocyte maturation in the mouse revealed that some mitochondria undergo gradual transformation in their ultrastructural appearance. In very young oocytes these mitochondria were already found to contain vacuoles, one in each such organelle. In somewhat older oocytes more mitochondria displayed vacuoles which generally appeared to be getting larger. These intramitochondrial vacuoles were found to be essentially optically empty structures surrounded by a single membrane. In favorable sections someof the developing vacuoles had a bottle-shaped appearance, the constricted end of which was attached to the inner limiting membrane of the mitochondrion. With further maturation of the oocytes vacuoles having a pear-shaped appearance became evident. An hypothesis was presented outlining the mode of formation of these vacuoles by expansion of the individual cristae. Intramitochondrial transformations occuring during both oogenesis and spermatogenesis in mammals were reviewed.
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  • 26
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    New York, NY : Wiley-Blackwell
    Journal of Morphology 121 (1967), S. 103-133 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The monotypic perciform suborder Luciocephaloidei possesses the following, previously unknown, salient morphological characters: a third joint, the nasopalatopterygoid, between neurocranium and suspensorium; a toothless and dorsally exposed prevomer; no pharyngeal processes on either parasphenoid or basioccipital; a tympanum-covered foramen exoccipitale in the saccular bulla as a hearing organ; a gular ossification; a craniovertebral joint with small exoccipital condyles widely separated from the basioccipital condyle; and a large physoclystic swimbladder with a notable caudal extension. The seemingly functionless gular-like mental ossification is considered a paleomorphic structure with a neogenetic development. Attenuation in longitudinal growth is evident in the derivatives and dermal additions of the mandibular arch and nasal capsule while other regions of the head have remained independent. The primary adaptive significance of the attenuation in the growth of the entire preorbital region is the accomodation of oral incubation. Secondarily the elongate jaws increase both the speed and grasping range of the bite in prey catching. The degree of jaw protrusion depends mainly on the length of the maxillary. The exaggerated length of the ascending processes of the premaxillaries may be the result of a positive differential growth rate within one growth field. The meaning of the preponderance of parallel-fibered cranial muscles is discussed in respect to holding functions, greatest possible excursion of the insertion with minimum loss of force, and muscle fiber length. Based on the overall morphology, the monotypic suborder Luciocephaloidei is retained.
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  • 27
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    Journal of Morphology 121 (1967), S. 135-157 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Osteology, myology and motion analysis of the head of the anabantoid fish Helostoma temmincki, a specialized filter feeder, has revealed six functional units: neurocranium, suspensory apparatus, opercular apparatus, hyoid apparatus, branchial apparatus and pectoral girdle. Interactions between the functional units take place through four couplings involved in opening and protruding the jaws. The first coupling is activated in the beginning of the opening cycle by the levator operculi muscle through the opercular apparatus, interoperculomandibular ligament and mandible. The second is activated during feeding by contraction of the sternohyoideus through the hyoid apparatus, interopercular, interoperculomandibular ligament and mandible. The third coupling is active during feeding and “kissing” by contraction of epaxial muscles through mediation of the neurocranium to the jaw apparatus. The fourth coupling is the only one active during air intake and involves contraction of the levator arcus palatini which abducts and rotates the suspensory apparatus forwards, causing the mandible to drop. The retention of isolated ancestral characters during mosaic evolution are explained in terms of the maintenance of couplings which represent functional associations of seemingly remote structures. When natural selection acts on one component of a functional unit or coupling, it essentially acts on all associated elements simultaneously causing character complexes to evolve in common evolutionary trends. It is feasible that functional analysis can separate primary from secondary evolutionary trends.
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  • 28
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    Journal of Morphology 122 (1967), S. 89-114 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Large dogs are able to deliver a powerful bite that generates considerable stress in the anterior, prehensile part of the jaws.In the upper jaw most of the biting force is borne by the anterior teeth. The palatal mucosa provides little resistance to deformation. It is easily compressed and rather mobile.In the lower jaw, the mucosa covering the upper surface of the symphysis receives a sizeable portion of the biting force. It is firmly attached to the underlying bone and possesses special connective tissue arrangements that enable it to transduce locally applied pressure to tension distributed over a broad area.
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  • 29
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Goldfish testes were nutritionally regressed in about 115 days regardless of season and without controlled light or temperature. A gonosomatic index (testes weight ″ 100/body weight) of the regressed fish was about one tenth that of spawning fish. The regressed testes were primarily composed of spermatogonia, spermatocytes, and connective tissue. Fish testes were maintained in a regressed state for over 200 days with no change in gonosomatic index. Fish with regressed testes appeared to be in a state of “pseudohypophysectomy” with respect to gonadotropin. Pituitary replacement and a diet of 5% of the body weight per day initiated spermatogenesis and brought the regressed testes to functional maturity in one month. The results suggest that spermatogonial proliferation and the maturation of sperm have different regulatory requirements.
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  • 30
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    Journal of Morphology 123 (1967), S. 1-16 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A theoretical analysis is made of the mechanical advantages of exoskeletons and endoskeletons. More complicated and realistic loading systems are considered than have been by previous authors. For all cases involving static loading, an exoskeleton would seem to be advantageous, but sometimes the advantage is quite small. If impact is considered, the advantage of exoskeletons becomes very much reduced, even on theoretical calculations; and it is likely that in life the advantage may be converted to a disadvantage, particularly in large active animals such as vertebrates.
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  • 31
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    Journal of Morphology 123 (1967), S. 43-61 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Silver stained Cordylophora were examined by light and electron microscopy, which provided a general picture of nerve cell forms and distribution for comparison with electron micrographs of osmium-fixed tissues from the same hydroid. Muscle, nerve and neurosensory components were studied in the nectophore of Nanomia (O. Siphonophora) and in the hydromedusae Sarsia and Euphysa by means of vital staining and optical and electron microscopy of epon sections; particular attention was given to relationships and interconnections between the cellular elements of the two marginal nerve rings. Mitochondrial size, numbers and types of vesicles and the occurrence of neurotubules and of parts of sensory cilia may provide useful ultrastructural clues for recognizing nerve elements, but serial sections are often needed to make identification conclusive.In Cordylophora and Nanomia, some neurites contain massed A vesicles (membrane-bounded dense granules) suggestive of neurosecretion (cf. reports on Hydra). However, a small type of A vesicle also occurs at synapses in Sarsia, indicating a probable role here in junctional transmission. Vesicles occur on both sides of some synapses (as previously reported for Cyanea) but on one side only in others, these being the first examples of polarized junctional ultrastructure in coelenterates.
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  • 32
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    Journal of Morphology 123 (1967) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 33
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    Journal of Morphology 123 (1967), S. 231-249 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A correlated light and electron microscope study was made of lymphocyte-epithelial relations in the appendix of normal rabbits, ranging in age from one week to ten months. The lymphocyte migration into the epithelium was very slight at one week. The lymphocytes were increased considerably in number from two weeks to three months, grouping into unique nests in the epithelium. The basement membrane began to be penetrated by migrating cells at one week and bacame discontinuous in older animals. At one and two weeks, the epithelial cells contained glycogen, which disappeared at three weeks. Degenerating cells as well as bacilli were found in the epithelial cells and in the macrophages of the nodules. The varied appearance of bacilli in the macrophages indicates that they were being digested. The lymphocytes in the epithelium were larger, having less crowded cytoplasm as compared with those in the lymph nodules. Many lymphocytes were in deep folds of epithelial cells. There was evidence favoring an intracellular position for some lymphocytes in the epithelium.
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  • 34
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: White Leghorn eggs were incubated to desired prevasular stages. Each embryo, upon its intact yolk and surrounded by albumen, was rolled from the shell into a sterile 50 ml beaker. In an uppermost position, the blastoderm was lightly stained with neutral red. Three types of localized cuts were made as indicated below, and the beaker-embryo unit placed in a sterile humidified chamber for further incubation. Results: (1) Unilateral cuts adjacent to the body and parallel with its axis blocked or suppressed formation of the vitelline artery on the cut side, even though healing occurred; (2) A specific site was found in the area pellucida opposite the sinus rhomboidalis which, when lightly cut perpendicular to the body axis, resulted in blockage or shifting of the final junction between aorta and vitelline artery as far cephalad as the thirteenth somite level. Formation of a dual final junction with the aorta also occurred. (3)Transverse cuts through the body axis and into the area pellucida bilaterally, frequently resulted in bilateral blockage or bilateral shifting. In still other cases, growth of a functional loop around the cut to connect the aortae in anterior and posterior segments with the vitelline artery were observed. Other unique circulatory patterns are described.Apparently, slight interference with the capillary plexus which precedes the vitelline artery causes anomalous development. Circulation is considered a major factor in arterial differentiation. Cutting probably alters the plexus and relation of its components to the onset of blood flow.
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  • 35
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Branches of the coronary arteries of normal human hearts, supplying both atria and ventricles, were found by fine dissection and have been named rami atrioventriculares. They comprise atrial branches from ventricular arteries and ventricular branches from atrial arteries. Their incidence was 74% in the 50 adult individuals studied. The subjects had committed suicide with a poison which did not damage the coronary arteries. The atrioventricular branches constitute communications across the coronary sulcus, thus establishing a continuity between the atrial and the ventricular arterial supply. Therefore, there is not invariably a sharp demarcation of blood supply between atria and ventricles, as has been commonly taught. Neither atrial nor ventricular branches consist exclusively of ascending and descending branches of the coronary arteries, as has been assumed. Atrioventricular branches can play a role in collateral circulation and may, in individuals who are born with them, provide an explanation for some of the variability in signs and symptoms incidental to heart attacks.
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  • 36
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The paper deals with the development of the salivary gland system in Melipona quadrifasciata anthidioides, which begins in the prepupal stage. The silk glands degenerate by autolysis at the end of the larval stage. Degeneration is characterized by cytoplasmic vacuolization and pycnosis of the nuclei of the secretory cells. The glandular secretory portion of degenerated silk glands separates from the excretory ducts. The salivary glands develop from the duct of the larval silk glands. The thoracic salivary glands develop from the ducts of the secretory tubules and the head salivary glands from the terminal excretory duct. The mandibular glands appear in the prepupa as invaginations of mandibular segments, and their differentiation to attain the adult configuration occurs during pupation. The hypopharyngeal glands have their origin from evaginations of the ventral anterior portion of the pharynx. A long tubule first appears with walls formed by more than one cellular layer. Then some cells separate from the lumen of the duct, staying attached to it by a cuticular channel in part intracellular. The initial duct constitutes the axial duct, in which the channel of the secretory cells opens. During the development of salivary and mandibular glands, they recapitulate primitive stages of the phylogeny of the bees. During the development of salivary glands system, mitosis accounts for only part of the growth. Most of the growth occurs by increase in size of cells rather than by cell division. In brown-eyed and pigmented pupae six days before emergence, the salivary gland system is completely developed, although not yet functioning.
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  • 37
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The caudal anatomy (caudal skeleton, musculature, vascularization, innervation, and urohypophysis) and swimming behavior of three clupeiform and three perciform fishes: Elops hawaiensis (Cupeiformes: Elopidae), Oncorhynchus nerka (Cupeiformes: Salmonidae), Chanos chanos (Clupeiformes: Chanidae), Kuhlia sandvicensis (Perciformes: Kuhlidae), Apogon menesemus (Perciformes: Apogonidae), and Gnathanodon speciousus (Perciformes: Carangidae), were studdied. The taxonomic significance of caudal structures was determined and evaluated by detailed examination of differences in caudal anatomy. An interpretation of functional significance of these differences was attempted by relating them to observed differences in swimming behavior. The swimming behavior was studied by the observation of swimming activities of fish while resting or cruising and while feeding in the aquarium, and by an analysis of each frame of an 8 mm movie film of swimming activities.There are certain consistent and basic differences between all three species of the order Clupeiformes and all three species of the order Perciformes in respect to caudal structures. Although certain caudal structures show overlapping in number and/or complexity of arrangement, they seem to indicate more complex structural organization in Clupeiformes than Perciformes. The differences confirm the conclusion of others that the order Clupeiformes is more “primitive” than the order Perciformes.With respect to caudal structures of the three clupeiform species studied, E. hawaiensis is the most “primitive” and, of the three perciform species studied, K. sandvicensis is the most “primitive.”Caudal structural variations from one species to another are related to the mode of adaptation to swimming as well as to the evolutionary status of the species.
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  • 38
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    Journal of Morphology 118 (1966), S. 11-41 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The axial filament of Sciara coprophila does not conform to the usual 9 + 2 filament pattern but consists, rather, of as many as 76 pairs of filaments which decrease in number from the anterior to the posterior region of the sperm. It is first seen at the base of the head in the shape of an indented oval. The axial filament varies in configuration along the remaining length of the sperm as one whorl or two connected whorls of filament pairs.The other structures of the sperm revealed by the light and electron microscopes are a homogeneous, dense, spear-shaped nucleus, a row of spherical dense bodies in the middle piece enclosed by the axial filament and of unknown nature and function and a single mitochondrial derivative.The mitochondrial nebenkern derivative consists of a large electron transparent region bordered by cristae and a smaller paracrystalline region located adjacent to the axial filament. The derivative arises as paracrystalline material in a medial nuclear indentation. The electron transparent material is first seen at the anterior end of the middle piece.Unlike other known insect sperm, but reminiscent of sperm capacitation in mammals, sperm maturation is completed in the spermathecae of Sciara 7 to 9 hours after insemination. It consists of the acquisition of sperm motility and elimination of the electron transparent region of the mitochondrial nebenkern derivative. The electron microscope reveals in mature sperm that the axial filament doublets have changed configuration and consist of a single whorl which encloses the paracrystalline rod. The process by which the major portion of the nebenkern derivative is eliminated occurs in four identifiable stages. Since sperm maturation does not appear to be intrinsically controlled, factors in the spermathecal fluid may play a role in its completion.
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  • 39
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The vascular architecture in the rabbit uterus was studied during pseudopregnancy. Uteri at 2, 3, 4, 6, 7, 8, 9, 11, 13, 16, 17, 18, 20, 24 and 28 days after sterile mating were subjected to one of four techniques: neoprene latex casts, transparent sections, frozen sections, and histological sections. Measurements were made microscopically of the thickness of myometrium and of the subepithelial capillary plexus in the different mucosal folds. In the estrous rabbit, the circular arteries in the uterine muscular layer give off arterioles which pass upwards, with a few branchings through the endometrium to the uterine lumen. These arterioles reach the surface of the mucosal folds and break up into the subepithelial capillary plexus. This plexus is connected to the tips of the venules which run down through the endometrium to the endometrial vascular plexus at the base of the endometrium: some of the venules connect with the circular venous vessels in the muscular layer. With advanced stages of pseudopregnancy, the capillaries among the glands become stretched and elongated. Maximal branching of the folds occurs at 4 to 9 days of pseudopregnancy. The “branching activity” was consistently higher in the placental than in the periplacental or in the obplacental folds. Such changes reached a maximum at 6 to 7 days p.c., after which the capillaries became gradually shorter and tortuous. The development of arterioles in the mucosa was marked at 3 to 6 days p.c. The thickness of the plexus in the periplacental fold and in the obplacental fold as a percentage of the thickness in the placental fold was highly correlated with the stage of pseudopregnancy. At 9 to 11 days p.c., these ratios reached a minimum of 70 to 80%.
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  • 40
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The forms of the tectorial membrane and its connections to the ciliary tufts of the hair cells have been studied in detail in 18 species of lizards and, less thoroughly, in three others. This group, which represents eight lizard families, exhibits three forms of tectorial membrane: a complete form that connects to all parts of the auditory papilla, an abbreviated form that makes this connection only in one limited region of the papilla, and a dendritic form in which the distal portion of the membrane subdivides into strands reaching all the hair cells.Sometimes the tectorial membrane connects directly with the tufts of the hair cells, but more often it makes this connection through intermediary structures. Seven types of such intermediary structures have been identified (if we include the sallet, which is not “intermediate” in a strict sense).Detailed descriptions are given of the various forms of tectorial membrane structures and their variations along the auditory papilla in 12 lizard species. The description for Iguana iguana is offered as representative of the iguanid pattern found in ten members of this family.Consideration is given to the functioning of the tectorial membrane, and also of the sallet, in the process of hair-cell stimulation.
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  • 41
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There were no lymphatic vessels and lymph nodes demonstrable in adult and larval Rana catesbeiana by a method that adequately demonstrated the same in mammals. Although the parenchymal arrangement in the lymphomyeloid organs is not exactly the same as in mammalian hemal nodes, nonetheless the vascular patterns of the lymph glands and jugular bodies are prima facie evidence that they function as blood-filtering organs among other probable functions. The vascular pattern of the lymph gland is that of a rete mirabile, particularly a venous portal system, inasmuch as the afferent and efferent vessels are venous in character and interposed between them is a labyrinth of sinusoids. This is not the case, though, in the adult organs. The vascular pattern of the jugular bodies is very much like the spleen, viz., artery-capillary-sinusoid-vein sequence. It is doubtful, however, if the propericardial and procoracoid bodies ever filter blood, because the smallest blood vessels in them are capillary in type Because of the absence of a well-defined capsule in some parts of the propericardial body, similarly to lymphoid follicles, especially in the mammalian gastrointestinal tract, it is probable that it filters tissue fluid. The last two organs are apparently mainly blood cell-forming organs. It is inferred from the vascular connections of the larval and the adult lymphomyeloid organs that they are not genetically related. This aspect was analyzed from earlier developmental data, but actual follow-up of the larval organs to the adult stage is still in progress.
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  • 42
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    Journal of Morphology 119 (1966), S. 467-475 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The history of the germ cells is traced from the time of hatching. The germ cells are larger in size and have faintly staining cytoplasm, clear cell outline and a distinct nucleus. They migrate by ameboid movement to reach the genital ridge and aggregate to lie against the gonadal epithelium prior to the formation of gonads. The germ cells are distributed along the gonad primordia.The period of sex differentiation occurs between the 5.4 mm to 12 mm stage. The testis formation is recognized by the presence of germ cell nests and the sperm duct cord. The formation of the ovary is noted by the enlargement of the germ cells of uniform size and the development of the ovarian cavity.The ovaries are described in four stages ranging from 21 mm to 135 mm fish. At 21 mm stage the ovarian cavity is continuous but is obliterated at 35 mm stage due to the projection of the ovigerous lamellae. The common opening for both the ovaries develops at 35 mm stage. The testes are described in four stages ranging from 23 mm to 135 mm fish. They differentiate more slowly and the first maturation division is seen at 90 mm stage.
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  • 43
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    Journal of Morphology 120 (1966), S. 9-21 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Larvae of the subfamily Amphipteryginae (Odonata) bear a tuft of tracheal gills on either side of the anus. The two tufts are derived from the laminae sub-anales, and are protected by the non-respiratory epiproct and paraprocts, and by plates derived from the cerci, lamina supra-analis or the lamina sub-analis itself. Each is approximately 1 mm long in mature larvae and comprises a series of repeatedly branching filaments, the terminal twigs of which are 5 to 10 μ in diameter. The total surface area of the tufts is approximately 5.0 mm2 in mature larvae of Devadatta, and more in the larvae of Pentaphlebia and Rimanella. Each tuft is connected by a large trachea to the longitudinal tracheal trunk. This large trachea divides many times, eventually forming a dense palisade of tracheoles in the epidermis of the filaments, immediately beneath the thin investing cuticle.
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  • 44
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth and morphogenesis of embryos of Aulocara elliotti (Thomas) at constant temperature are described in terms of 27 discrete morphological stages with four stages designating blastokinesis. The developmental variability of two series of embryos reared from a single wild population in two different years is compared. A bibliography to studies on other embryos of the Acrididae is included.
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  • 45
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histological serial sections of spleens from the adult raccoon (Procyon lotor) and woodchuck (Marmota monax) were processed for microscopic examination. Observations related to various aspects of the internal vascular pattern in the spleen of the raccoon and woodchuck demonstrated features that were characteristic of the respective animal. The spleen of the raccoon possess well-developed ellipsoid sheaths, whereas these same structures were not as prominent in the spleen of the woodchuck. The spleen of both mammals examined demonstrated the presence of an anastomosing series of venous sinuses within the red pulp tissue and may be classified as sinusal in nature.
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  • 46
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    Journal of Morphology 121 (1967) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 47
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    Journal of Morphology 121 (1967), S. 55-70 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Light and electron microscopical studies allow a descriptive account to be given of he morphogenesis of the egg chamber of Drosophila melanogaster. The study demonstrates that the mitotic products of a single cystoblast generate a branching chain of 16 inter-connected cystocytes. Two specific cystocytes enter meiotic prophase, while the rest become nurse cells. The two pro-oocytes form synaptinemal complexes in their nuclei. However, one of the two cells later switches back into the nurse cell developmental pathway. The elongation of the synaptinemal complexes is described, and estimates are made of the time involved in their formation. These complexes continue to be synthesized long after the DNA replication which gives the oocyte its 4C DNA content. This finding implies that at least some genetic crossing over follows DNA replication. Evidence is presented that cells undergoing crossing over are most efficient in repairing radiation-induced chromosomal breaks. Suggestions are given as to the mechanisms by which (1) cell division is inhibited once 16 cystocytes are formed, (2) the future cleavage planes of cystocytes are programmed, (3) the pro-oocytes are differentiated from nurse cells, and (4) the oocyte is chosen from the twin pro-oocytes. The contrasting behaviors of the oocyte and nurse cell nucleoli are described. During oogenesis nucleolar synthesis of ribosomal RNAs is suppressed in the oocyte and concurrently stimulated in the nurse cells. It follows that the nurse nuclei are the major sources of the prodigious quantities of ribosomes found in the ooplasm of the mature oocyte.
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  • 48
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The enigmatic lophophoral organs of phoronids are demonstrated to by accessory sex glands. In the hermaphroditic Phoronis vancouverensis, each mature adult has two pairs of such glands: female nidamental glands that facilitate the temporary brooding of the embryos and male accessory spermatophoral organs that function in spermatophore elaboration. Functional males of Phoronopsis harmeri have complex accessory spermatophoral organs while females of this non-brooding dioecious species lack accessory sex glands.In both species, coelomic spermatozoa are accumulated within the nephridia and passed en masse into the partially enclosed spermatophoral organs. There each sperm mass is molded into a characteristic shape and encased in one or more membranes before release as a spermatophore into the ambient water. The structure of the spermatophore is characteristic for each species and is correlated with the functional morphology of the distinctive spermatophoral organs.The existence of spermatophores, the non-primitive nature of the spermatozoa, and additional features of reproductive biology dictate that fertilization is internal in these species, but attempts to determine the means of sperm transfer proved futile. Reproductive potential and behaviour of male Phoronopsis, means of gamete segregation in Phoronis, and general pattern of reproductive biology for both phoronids were also studied.
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  • 49
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    Journal of Morphology 120 (1966), S. 391-396 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Giant salamanders, Amphiuma means, measuring 240 to 280 mm from snout to vent, tolerate induced anoxia for six hours. Most of the cardiac glycogen (beta units) is depleted within the first hour of anoxia but a few scattered units remain after six hours. The suggestion that cardiac glycogen is a stand-by energy source which enhances the energy available to the heart during anoxic strain is reasonable. Beta units are stored in the heart as opposed to the larger alpha units in the liver. The smaller beta units are probably more easily metabolized than the larger alpha units due to their greater surface area per volume ratio and dispersal around the numerous cardiac mitochondria.
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  • 50
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    Journal of Morphology 120 (1966), S. 397-423 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoplasmic microtubules and axial unit tubules were studied in both sectioned and negatively-stained material. Walls of microtubules of frog lung-fluke (Haematoloechus medioplexus) spermatozoa have a helical substructure, while those of the flagellate, Trypanosoma lewisi, are composed of ten longitudinally-oriented filaments. Cross-bridges occur between some filaments of trypanosome microtubules. Doublet tubules of axial units in both cell types are structurally similar to the trypanosome microtubules, which may indicate similarity of function. Microtubules of fluke spermatozoa appear to be somewhat rigid, are resistant to sonication, and are considered to be mainly supportive. Circular profiles of wall subunits are seen in transverse sections of microtubules of both cell types and in doublet tubules of the trypanosome. Comparisons are made between sectioned and negatively-stained material; while negative-staining better reveals the fundamental substructure of microtubular elements, some distortion appears to occur. In connection with this research, a brief preliminary article demonstrated the presence of subunits in the walls of cytoplasmic microtubules of fluke spermatozoa (Burton, '66). Also, it was shown that the wall of these tubular elements possesses a helical structure, and a diagrammatic representation of the wall structure was set forth.
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  • 51
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    Journal of Morphology 121 (1967), S. 19-28 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the column of hydra, tissues continually move away from a region located just underthe whorl of tentacles. Above this subtentacular region, tissues proceed into the hypostome and tentacles; below it tissues pass into the buds or continue down the stalk. These movements represent a steady state pattern of tissue renewal in which column growth is balanced by tissue loss at the body extremities. But the existence of a subtentacular zone in which tissue appears stationary does not necessarily indicate that growth is restrictedto this region, as is commonly stated.The body column of hydra can be viewed as an expanding cylinder whose elongation is balanced by tissue loss at the two ends. In such a body there must be one region from whichtissue appears to emanate, regardless of how growth is distributed along the cylinder. Only the rates at which tissues move will be characteristic of the underlying growthpattern. In Hydra littoralis, the measured rates of tissue movement down the gastric column are consistent with the distributions of mitotic figures, which indicate that growth is spread out along the column.
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  • 52
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    Journal of Morphology 121 (1967), S. 71-80 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Profiles of fresh chick lenses of 5, 8, 11, 14, 17 and 20 days embryological age were photographed and from tracings of these profiles, volumes were calculated using a formula for volume of a solid of revolution. Accurate volumes were also obtained by assuming the lens to be two half oblate spheroids of different minor axis, or, better, two half-solids of profile (x/a)k + (y/b)k = 1. In addition, the k in this equation described well the curvature of the lens profiles and thus provided a quantitative measure of developing lens shape. Lens diameter, depth and shift of equatorial diameter upon lens axis as a function of age were also studied.
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  • 53
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    Notes: Ductuli efferentes in four examined genera of family Didelphidae are organized into highly convoluted tubules, located within a conical body adjacent to the vascular plexus supplying the testis. They have yellowish-green color in the adult Didelphis virginiana and grey pink color in other genera. The ductuli efferentes in all examined animals are lined by very low columnar cells, covered by microvilli or booth cilia and microvilli.Histochemical analysis reveals several types of cytoplasmic granules in the genera examined. A single sperical body about 1.5 μ in diameter is found in epithelial cells of the four eyed opossum (genus Philander); this body stains positively for RNA and non-histone protein, and appears granular under the electron microscope, without a limiting membrane. Abundant cytoplasmic bodies in the Virginia opossum show strong reactions for SH groups; these granules may be responsible for the green color of the ductuli in this species. Ultrastructural studies show that the morphology of membrane limited granules in the ductuli of the examined genera is characteristic for each genus. Abundant pinocytotic vacuoles in the apices of these cells and a strongly positive alkaline phosphatase reaction suggest a marked absorptive activity of epithelial cells.
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  • 54
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    Journal of Morphology 121 (1967), S. 179-207 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Detailed descriptions are presented of morphogenetic and histogenetic events occurring in the membranous and bony labyrinths, sensory areas, acoustic ganglia, and acoustic centers of the hindbrain of the chick embryo, stages 11 to 45. Major morphogenetic changes occur between stage 11 and stage 30. During this period primordial ganglionic neuroblasts are segregated from the otic epithelium and differentiate into the bipolar neuroblasts of the vestibular and cochlear ganglia, neuroblasts of the alar plate in the acoustic region of the rhombencephalon differentiate, migrate, and are organized into acoustic nuclei, and the otic cup closes to form a vesicle which undergoes complicated structural changes to become a labyrinth. Morphological events in neural structures are closely followed by structural changes in the labyrinth. Minor morphological changes continue to occur through stage 44. The histogenetic period, stage 26 to 38, is the same for all parts of the acoustic apparatus. Minor histogenetic events occur up to hatching. In this period, differentiation of ganglionic and central neurones precedes differentiation of sensory cells.
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  • 55
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    Journal of Morphology 121 (1967) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 56
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    Journal of Morphology 121 (1967), S. 223-239 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: With the help of PF and PAVB bulk-stained preparations and sections the neurosecretory system of Ranatra elongata has been described. Two medial, each of 9-10 cells, and two lateral, each of 3-4 cells, groups of neurosecretory cells have been observed in the protocerebrum. Only the A-cells have been found to be positive to PAVB histo- and cyto-chemical technique. Axons of the A-cells after traversing the proto- and deuto-cerebrum emerge from the tritocerebrum as the NCC I. The NCC I after bypassing the corpora cardiaca penetrate the aorta wall. There is no physical continuity between the corpora cardiaca and the NCC I and the two are separable. The NSM from the A-cells, transported by their nerve fibers, has been observed in the aorta wall. On the basis of large accumulation on NSM in the aorta wall the latter has been considered as the storage-and-release organ for the A-material. Corpora cardiaca are found to be devoid of A-material. Axons from the B-cells, after emergence from the tritocerebrum as the NCC II, have been observed to penetrate the corpora cardiaca. On the basis of ample amounts of B-material the glands have been considered as the storage-and-release organ for the B-material only.Observations are compared with results on related species and it is concluded that two independent organ complexes constitute the neurosecretory systemt of R. elongata. The A-cells, their pathways, the NCC I, and the aorta wall comprise the first; and the B-cells, their pathways, the NCC II, and the corpora cardiaca the second. The former is concerned with the elaboration, transportion, storage-and-release of the A-material and the latter with the B-material. Finally arguments are presented to include the aorta wall in the neurosecretory system.
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  • 57
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    Journal of Morphology 121 (1967), S. 311-321 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy of the ventral neck region of the scincid lizards Chalcides ocellatus and Scincus scincus is presented and is found to be similar to that of other lizards as described in the literature. The internal carotid artery arises by 3-5 roots from the dorsal side of the ascending limb of the carotid arch. During its first part, the internal carotid artery is completely divided into two nearly equal channels. The carotid sinus is more complicated in Chalcides than in Scincus. In lizards, it may be homologous to the carotid labyrinth of fishes and amphibians. Around the origin of the internal carotid artery are two kinds of epithelioid cells scattered in the adventitial connective tissue: a- large cells with rounded, faintly stained nuclei, and little, clear cytoplasm; b- cells with small darkly stained nuclei. Both kinds of cells appear to represent different levels of secretory activity. The number of the large cells increases with greater complexity of the carotid sinus. The cells also increase in size and number during summer (sexual period); this is especially true in younger animals. The epithelioid cells are considered to be homologous to the carotid body of higher vertebrates. The carotid sinus and epithelioid cells together form a closely interrelated system which may be intermediate between the carotid labyrinth of fishes and amphibians, and the carotid body of birds and mammals.
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  • 58
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    Notes: The fine structure of the nerve cell types in the white planarian Procotyla fluviatilis were described. Ganglion cells comprise the major portion of the brain. These cells are irregular in shape with several cytoplasmic processes and contain ribosomes, a sparse endoplasmic reticulum, microtubules, lysosomes, and a Golgi apparatus with numerous small vesicles. Granule-containing cells are situated in the peripheral regions of the brain and along the nerve cords. These cells contain ribosomes, rough-surfaced endoplasmic reticulum and a Golgi apparatus with associated dense granules. The granules occupy most of the cytoplasm and are ∼ 750A in diameter with moderately dense contents, ∼ 750A with opaque contents, and ∼ 1000A with contents of medium density. These granules are similar to those in the nervous systems of higher animals that contain epinephrine, norepinephrine, and neurosecretory substance, respectively. Each cell contains predominantly one type of granule although there is some intermixing of granules and intermediate types between the three most abundant granules. Small clear vesicles, resembling cholinergic synaptic vesicles, and all types of dense granules occur in the neuropil and within nerve endings.
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  • 59
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    Notes: A study of the ingestion of particulate matter from the pallial space located between the shell and the outer surface of the mantle of Isognomon alatus and Pinctada radiata was undertaken with the aid of the electron microscope. For this purpose colloidal thorium dioxide (thorotrast) was introduced into the pallial space for periods of 1-5 days after which time the mantle was excised and prepared for examination with the electron microscope. After 24 hours thorotrast micelles were observed in the pallial space, on the surface of the microvilli, in small pinocytotic vesicles between the bases of the microvilli, in vacuoles undergoing coalescence and finally in large dense bodies (lysosomes). Amoebocytes in the pallial space also participate in the removal of particulate matter in a manner similar to that described for the surface epithelium. During active ingestion the Golgi apparatus changes from a vesicular to a lamellar form. The method of ingestion observed in the surface epithelia and the amoebocytes is similar to the ingestion of protein and other particulate material reported for a variety of vertebrate tissues.
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  • 60
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    Journal of Morphology 122 (1967), S. 231-247 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The proventriculus of White Leghorn chick embryos (stages 29-45) newly-hatched chicks, and adult chickens were frozen, sectioned in a cryostat and treated histochemically to identify localizations of alkaline and acid phosphatase, adenosine triphosphatase, 5-nucleotidase, nucleotide-diphosphatase, non-specific glycerophosphatase, glucose-6-phosphatase, non-specific esterase and succinic dehydrogenase. Ribonucleic acid, proteins and acid mucopolysaccharides were identified in tissues fixed in FAA.Acid phosphatase, nucleotide-diphosphatase, adenosine triphosphatase, succinic dehydrogenase, ribonucleic acid and proteins were present in the cells of the deep glands at all stages of development. Alkaline phosphatase and 5-nucleotidase were found only in mesenchymal derivatives of the proventriculus. After the chick begins swallowing and digesting albumen, enzymatic activity increased and non-specific esterase became very reactive.The surface epithelium is covered with a mucous coat. Ribonucleic acid, non-specific esterase, acid phosphatase and nucleotide-diphosphatase were localized in the basal portions of the epithelial cells. The functional significance of these different patterns is discussed.
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  • 61
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    Journal of Morphology 122 (1967), S. 265-305 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Basal tail constriction occurs in about two-thirds of the species of plethodontid salamanders. The constriction, which marks the site of tail autotomy, is a result of a reduction in length and diameter of the first caudal segment. Gross and microscopic anatomical studies reveal that many structural specializations are associated with basal constriction, and these are considered in detail. Areas of weakness in the skin at the posterior end of the first caudal segment, at the attachment of the musculature to the intermyotomal septum at the anterior end of the same segment, and between the last caudosacral and first caudal vertebrae precisely define the route of tail breakage. During autotomy the entire tail is shed, and a cylinder of skin one segment long closes over the wound at the end of the body.It is suggested that specializations described in this paper have evolved independently in three different groups of salamanders.Experiments and field observations reveal that, contrary to expectations, frequency of tail breakage is less in species with apparent provisions for tail autotomy than in less specialized species. The tail is a very important, highly functional organ in salamanders and it is suggested that selection has been for behavioral and structural adaptations for control of tail loss, rather than for tail loss per se.
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  • 62
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    Journal of Morphology 123 (1967) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 63
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    Notes: Esophagi of White Leghron chick embryos, six days to hatching, were fixed in 5% glutaraldehyde in a cacodylate-sucrose buffer, postfixed in 1% OsO4, dehydrated and embedded in Araldite. Tissues were sectioned with glass knives and viewed with a Philips EM 100C. The epithelium in early stages of development is characterized by small intercellular spaces, few cell processes and few desmosomes. In contrast the differentiated epithelium contains numerous cell processes, large intercellular spaces and numerous desmosomes. Mucin appeared in the mucous glands at 17 days.
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  • 64
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    Journal of Morphology 117 (1965) 
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  • 65
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    Notes: Implants were made into forelimbs of Triturus viridescens using fresh, frozen and boiled kidney and liver of T. viridescens and R. pipiens. Limbs were recovered at intervals up to 70 days post-implantation.Kidney implants from Wisconsin R. pipiens gave twice as many extensive accessory structures as did Vermont frog kidney. Total induction percentages, however, were similar.Quantitative and qualitative parameters for implant-induction of accessory structures were investigated. The decrease in antigenicity and increased rate of cytolysis of frozen implants resulted in increased similarity between frog and newt kidney in rate and pattern of breakdown and in rates of induction. Modification of rate and duration of the release of the stimulating factor from the implant did not result in induction by liver implants.No evidence was found for any increase in innervation prior to or coincident with blastema formation. Implantation and implant cytolysis may cause hypersensitivity of limb tissues to the normal innervation pattern or trophic stimuli from the implant may act with those from the injured limb tissues to produce growth.The general pattern of host reaction to the implanted material was studied and described.
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  • 66
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    Notes: Morphological aspects of lateral line system of Gymnotidae, Mormyridae and Gymnarchidae were studied: “Ordinary” and specialized sense organs were identified and their somatic distribution and their relation to the lateral line nerves established. An attempt was made to classify the specialized sense organs of the lateral line system in these families. The morphological results are discussed in relation to recent physiological data permitting identification of one of the specialized sense organs as a newly recognized sense organ, the electroreceptor.
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  • 67
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    Journal of Morphology 117 (1965), S. 251-269 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The genetics and anatomy of the homoeotic mutant labiopedia (lp) of Tribolium confusum is described. The mutant is the second known among the insects to affect the mouthparts. The two-segmented labial palps of the larva are completely replaced by leg-like appendages resembling the prothoracic legs and exhibiting the apex of the trochanter and all parts distal to the trochanter. The labial palps of the pupa and adult are likewise replaced by legs. The three-segmented palps of the adult are replaced by appendages closely similar to the prothoracic legs in many characters and exhibiting the apex of the coxa and all other parts of a normal walking leg. The legs have never been seen to move although they are supplied with labial nerves and an almost complete, though highly reduced, set of muscles. The labial appendages are invariably leg-like and well-developed, failing to show the range of variability which is commonly observed in homoeotic mutants. The leg-like form of the heteromorphic organ is in striking conformity with the appendicular origin of the palps.The lp gene is recessive and sex-linked, with lethal to semilethal effects. It is the third sex-linked gene discovered in Tribolium confusum and the first sex-linked homoeotic mutant known among the insects. Since the inheritance of lp is entirely in the manner of a sex-linked gene, it most probably is located on the original X chromosome, unless the translocated autosomal portion attached to the Y has become inert.
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  • 68
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    Journal of Morphology 117 (1965), S. 271-293 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: Light and electron microscope studies of the digital lamellar setae of geckos and anoline lizards demonstrate that the free ends of the setae consist of flattened spatulas of less than 1 μ in width. The anoline setae are simple structures usually less than 30 μ in length and with a single terminal spatula to each seta. In contrast the setae of geckos are complex structures of about 100 μ in length, with numerous branchings, and having many spatulas per seta. The spatulas of Gekko and Aristelliger were smaller (0.2-0.4 μ in width) than the spatulas of Anolis (0.8 μ in width). The electron microscope studies indicate that the scales of lizards appear to be covered with small epidermal spines (1.5 μ long). The setae of anoles and geckos are considered to have evolved independently from these more primitive epidermal spines. It is further suggested that the mechanism that allows the lamellae to adhere to the substratum is a surface phenomenon. The spatulas provide a large surface that is in contact with the substratum and thus produces a large total frictional force. The α layer of the lizard stratum corneum can be readily identified in the lamellae. However, the structure of the β layer is not easily interpreted and there is evidence of a fibrous layer between the Oberhautchen and the α layer in the skin of the outer lamellar surface.
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  • 69
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    Notes: The muscles and motor and sensory nerves of the pregenital abdominal segments were described and discussed in relation to the nerves and muscles of the thorax, as described by other workers. Each of the integumental muscles was named and described with regard to its location, function and innervation. Differences among segments of the same sex and between sexes were noted.A description of a longitudinal muscle, named here the hyperneural muscle, was included. The muscle overlies the abdominal portion of the nerve cord and may be derived from the ventral diaphragm. The most notable features of its structure are chiasmata of fibers which occur at points along its length and which show consistent relationships to the nerve cord and median nerve.A previously undescribed organ, located ventrally at the intersegmental fold, having dual innervation and showing stretch receptor function was described.
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  • 70
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    Notes: The rat submaxillary salivary gland has five distinct parenchymal zones.1Acini consist of secretory and myoepithelial cells. An extensive network of canaliculi connect the many cells within an acinus to the main lumen. The fine structure of acinar secretory cells suggests that they are capable of great synthetic capacity; each cell having a large amount of ergastoplasm, many Golgi zones, and a great amount of secretory material. It is proposed that these cells are of the continually secreting type.2Intercalated ducts consist of cuboidal cells and myoepithelium. This segment connects the acini to the main conduit system of the gland. The fine structure of the cuboidal cells indicates that they are essentially nonsecretory.3The granular duct consists of three types of columnar cells; (a) dark narrow cells which contain many free ribosomes but no ergastoplasm or granules, (b) light granular cells which have varying amounts of ergastoplasm and granules, (c) dark granular cells which are full of granules while the other cell constituents including the nucleus, occupy a basal position. It is proposed that these three cells represent different secretory stages of the same cell type. This supports the interpretation that secretion in these cells is not continuous, but cyclic in nature.4The striated duct forms a small portion of the total gland parenchyma and consists of tall columnar cells with extensive infolding of the basal plasma membrane, relatively little ergastoplasm and very few granules. It seems likely that ion and water metabolism is a specialized function of this segment.5The excretory duct consists of three cell types: (a) tall columnar light cells, (b) dark columnar vesiculated cells and (c) small basal cells. The basal infoldings of these cells and the arrangement of many capillaries around these ducts suggests that this segment is primarily concerned with water transport.
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  • 71
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    Notes: It was demonstrated that the germinal (surface) epithelium around the mouse ovary consists of simple squamous, cuboidal and columnar arrangements of cells. With the electron microscope it was shown that these cells have the usual cytoplasmic constituents such as the Golgi complex, mitochondria, ergastoplasm, and free ribosomes. Their nuclei are surrounded by a bilamellar envelope with coarse granular masses of nuclear material being distributed along its inner surface. From the surface of these cells extend numerous microprojections which usually are irregular in squamous cells, but are villus-like on the cuboidal and columnar forms. These microvilli appear to be simply extensions of the cell surface and apparently reflect the capacity of mesothelium for such specialization at its free surface. The intercellular boundaries are seen to consist of wavy, downward extensions of the plasma membrane or a complex irregular interdigitation of coarse lateral processes. The latter form is especially prominent between squamous cells. A membrane is present at the basal cell surface. The observations concerning the presence of microprojections and the nature of the intercellular boundaries were discussed in the light of the controversies on these subjects which appear in the early literature. The possible permeability of the germinal epithelium and its functional significance during maturation of the ovary were also discussed.
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  • 72
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    Journal of Morphology 117 (1965), S. 401-423 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Pre-copulatory behavior of male Aedes involves pursuit, tarsal contact, ventral orientation, and terminalial contact. Copulation itself involves seizure of the female's cerci by the male's claspers, extension of the male's paraprocts, erection of the aedeagus, and ejaculation. The male's ability to copulate is prevented by damaging or removing his seventh abdominal segment. If this segment is left intact, his freshly removed abdomen can copulate with a freshly isolated female's abdomen when their terminalia are rubbed together appropriately. The male's genital apparatus accurately “recognizes” the terminalium of an inseminated female, and forced-copulation cannot be induced. The claws at the ends of the male's claspers are inserted into the bases of the female's cerci. The thumbs of the apical paraprocts of the male fit into a temporary coital cavity within the upper vagina. The hooks of the male's apical paraprocts are inserted into the female's cloacal hollow. The teeth on the distal end of the aedeagus ratchet into the teeth on the dorsal vaginal valve and evert the upper vagina. The posterior ends of the seminal vesicles and accessory glands open and contractions of these organs release seminal material only into the bursa of the female.
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    Journal of Morphology 119 (1966) 
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    Notes: Hair follicles are initiated in mice homozygous for Strong's luxoid gene at the normal times. The dermis from 16 days of gestation to nine days after birth lags in development. The adipose layer instead of enlarging at the normal time of three days after birth delays until nine days. The growth of the first cycle hairs is inhibited, particularly on dorsal surfaces. Some follicles of all types degenerate. The surviving follicles enter telogen at seven days after birth, after forming only short unpigmented or poorly-pigmented hairs. Many follicles immediately begin a second cycle of growth, in which more normal hairs develop and a substantial adipose layer forms. No alopecia develops on ventral surfaces, but growth of the first cycle ceases and the second cycle commences earlier than normal; the hairs formed are abnormal. Abnormal hair growth in Strong's luxoid homozygotes may be a result of the retarded growth of the dermis or both defects may be secondary to a more fundamental defect.
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  • 75
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    Journal of Morphology 119 (1966), S. 7-19 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gross and histological examination of lizard oviducts was made in 11 species of the family Iguanidae, and in one species of each of the families Gekkonidae and Eublepharidae. Lizard oviducts are bound dorsally by a mesentery which is continuous with the peritoneum, and ventrally by a smooth muscle band which extends from the posterior segment of the vagina to the base of the infundibular ostium. The musculature of the vagina consists of an inner circular smooth muscle layer which is thickened posteriorly, and an outer longitudinal layer which is arranged into longitudinal folds at about the utero-vaginal transition. In iguanid lizards the vaginal mucosa is arranged into longitudinal folds that extend the entire length of the vagina. Posteriorly, the folds are high and reduced in number. Anteriorly, they decrease gradually in height and become more numerous. In Phyllodactylus homolepidurus fold height and number remain essentially constant through the vagina. Seminal receptacles in the iguanids occur principally in the anterior segment of the vagina. Receptacles in P. homolepidurus (Gekkonidae) and Coleonyx variegatus (Eublepharidae) appear to be confined to the tube between the uterus and the infundibulum. Most receptacles are located adjacent to the oviducal mesentery and to the smooth muscle band.
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  • 76
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: 1Neurosecretary cells in the central nervous system of the adult blowfly, Phormia regina Meig., have been examined histologically using the parparaldehyde-fuchsin and Gomori's staining method. Six groups of the neurosecretory cells occur in each hemisphere of the brain, the medial, frontal, lateral A, lateral B, posterior I and posterior II groups. In the subesophageal ganglion, four B-cells and two A-cells are present. In the thoracico-abdominal ganglion, ten A-cells are found in the thoracic region and a total of about 50 A- and B-cells in the hind part of the abdominal region.2A comparison with the neurosecretory system of two other species of blowfly, Calliphora erythrocephala Meig., Sarcophaga bullata Parker, and the housefly, Musca domestica L., showed similar arrangements and grouping.3Neurosecretory granules have been observed along the axons originating from the medial neurosecretory cells of the brain, and the thoracico-abdominal ganglion. The granules originating from the medial groups can be traced directly to the corpus cardiacum from which they move to the aorta, crop duct and cardia through axons.4There is with advancing age a gradual increase in the size of cell bodies and nuclei of the median neurosecretory cells in both females and males of Phormia regina, and also a decrease in stainable granules. This increase in size is dependent on nutrition, with no increase in water alone, a slight increase on sugar, and a maximum increase on sugar and liver. Corresponding increases in size occur in the ovaries in connection with feeding the same substances.
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  • 77
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    Journal of Morphology 119 (1966), S. 101-119 
    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 the external ears and the ultrasonic cries produced by one member of the single family of Megachiroptera and six representatives of the Vespertilionoidea of the Microchiroptera have been described. All the specimens were intra-vitally fixed and the preparations have been examined, photographed and measured. Brief notes are given on the middle ear and the following measurements have been made on the cochlea: the general size of the cochlea in various dimensions, the width and thickness of the basilar membrane, the size of the spiral ligament and the height of the cells of Claudius. In conclusion it can be said that there are marked differences in the structure of the cochleae of the two suborders, as well as within the superfamily Vespertilionoidea.
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  • 78
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    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The chemoreceptors of Limulus polyphemus (L.) are polyneuronal sensilla found in the spines of the coxal gnathobases of each walking leg, the spines of the chilarial appendages, and the chelae of all the limbs. Each sensillum contains 6-15 bipolar sensory cells that share a single pore in the cuticle. The dendrites of the sensory cells of each sensillum course to the cuticle together. These attenuate sharply and enter a canal in the cuticle as a very narrow terminal thread. The dendrites retain their identity in the thread, but with the light microscope, they are usually not visible individually. Each thread, consisting of 6-15 dendrites, is accompanied to the cuticular surface by a cuticular tubule found within the canal. The chemoreceptor sensilla of the gnathobase, chilarium, and chela, the temperature organs of Patten, and the flabellar receptor organs all have the same basic organization. In general this is the same structural plan shown by chemoreceptors of other arthropods. Several different mechanisms of peripheral physiological interaction among receptor cells are possible with a sensillum organization like that described here for Limulus.
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  • 79
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The hemolymph of the horseshoe crab, Limulus (Xiphosura) polyphemus, contains a single cell type. The hemocytes are ovoid and contain many refractile granules. One-half to one minute after the onset of clotting the hemocytes swell and a hyaline cytoplasmic ring, essentially devoid of granules, appears about their circumference. During this time the granules disperse and the nucleus becomes visible. Three to five minutes following the initiation of clotting, the cell extends long pseudopodial processes. Phase contrast time-lapse cinematography reveals that the cells are extremely motile during this phase. Concomitant with these changes, many of the granules lose their refractility and one by one disappear from the cytoplasm leaving what appears to be a vacuole.Electron micrographs of native (un-clotted) hemocytes and of clots fixed in glutaraldehyde and post-fixed in osmium reveal that the membrane-bounded granules of native cells are very dense and homogeneous with no evidence of an internal structure. One-half to one minute after clotting, however, they become less dense and 250 Å microtubules spaced at ca. 500 Å intervals appear parallel to the long axis of the granule. Further degradation of the granule ensues and involves (a) change to a spherical shape, and (b) further decrease in density and better resolution of the microtubules. The microtubular component subsequently disintegrates leaving a membrane-bounded granule containing particulate material. Finally, the membrane of the granule fuses with the plasma membrane and the components of the granule are dispersed in the plasma where they presumably contribute to the formation of the gelatinous clot.
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  • 80
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    Journal of Morphology 119 (1966), S. 259-276 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The segmental muscles in the intestinal region of the body of Hermodice carunculata are described as well as the gross anatomy of the associated nervous system.The form of normal locomotion and the characteristic alarm reaction are described and interpreted in terms of fluid pressure within the body cavity and the action of appropriate groups of segmental muscles.Brief remarks on the habits of H. carunculata conclude the paper.
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  • 81
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    Journal of Morphology 119 (1966) 
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  • 82
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Classical studies of the nervous system of the leech revealed that there were specific types of very large glial cells associated with various parts of the neuron. Recent microelectrode studies demonstrated that there was a low resistance to the flow charge from any one of these large glial cells to another. The present study describes a previously unreported type of glial cell, the glial cell of the fascicles. These cells, which resemble the glial cells of the connectives but are smaller, are found in the fascicles of axons that unite the connectives to the neuropil. Thus, these cells are located between the glial cells of the connectives on the one hand and the glial cells of the neuropil and packets on the other and must be taken into account in considerations of the low resistance to the transfer of charge from one glial cell to another.
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  • 83
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    Journal of Morphology 120 (1966) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 84
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    Journal of Morphology 119 (1966), S. 425-433 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nucleoli of cells of the adult mouse were examined by staining with toluidine blue after removal of deoxyribonucleic acid from tissue sections by deoxyribonuclease treatment.The nuclei of each cell type examined contained one or more nucleoli. This was observed even in lymphocytes and neuroglia, although these cells have occasionally been described as anucleolated. In mature spermatids and spermatozoa, however, it was not possible to detect a nucleolus.The distribution of the number of nucleoli in many diploid cells exhibited a mode of two or three nucleoli per nucleus, and a range from 1 to 6 nucleoli.In presumedly diploid hepatic nuclei, the maximum number of nucleoli was six; but in presumedly tetraploid hepatic nuclei, it was 11. Thus, nearly twice as many nucleoli are present when the chromosome number is doubled. In view of this observation, it is suggested that six nucleolar organizers are present in the diploid chromosomal complement of the mouse. However, through failure of some nucleolar organizers or more probably through fusion of nucleoli, the number of these organelles in most nuclei is less than six.
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  • 85
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    Journal of Morphology 120 (1966) 
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  • 86
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    Journal of Morphology 120 (1966), S. 233-265 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The epidermal setae and the spinules of the digital lamellae of anoline and gekkonid lizards are shed periodically along with the rest of the outer layer of the skin. These structures are developed within the lamellae prior to ecdysis. The setae are larger and more complicated than the spinules and begin their development first. The setae of Anolis start as aggregations of tonofibrils beneath the plasma membrane of the presumptive Oberhautchen cells. These cells are arranged in rows parallel to the surface, several cell layers beneath the alpha layer of the skin. The developing setae protrude into the clear layer cells as finger-like projections, with the tonofibrils longitudinally oriented in the direction of growth. About 100 setae are formed by each Oberhautchen cells in Anolis. In late development, the clear layer cells lose their cellular contents and when shed along with all distal cells, retain a template of the new setae or spinules. The spinules and setae are formed before the fibrous and alpha layers of the new skin. The fibrous layer, which occurs only on the ventral (outer) layer of the lamellae, and the Oberhautchen with its setae and spinules, is considered the beta layer. The alpha layer, which occurs adjacent to the fibrous layer on the ventral surface and adjacent to the Oberhautchen on the dorsal (inner) surface, is morphologically identical to that of mammalian α keratin. The shed lizard skin consists of the alpha and beta layers as well as the degenerating cells of the outer epidermal generation, and the clear layer. The clear layer that is shed shows the template of the new setae and spinules developed in the new skin layer. The separation of the new from the old skin occurs along the intercellular space between the clear layer cells and the new Oberhautchen. The alpha layer of the skin is not fully keratinized at shedding. The setae of the digital lamellae of lizards represent unique epidermal structures  -  intracellular keratinized microstructures.
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  • 87
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The view is commonly held that the exclusive source of axonal substance is the neuronal cell body. The results of the present study, employing techniques of light and electron microscope autoradiography, indicate that substances of metabolic importance may reach the axon from intercellular fluids by way of the Schwann and myelin sheath. Tritiated l-histidine was injected intraperitoneally into the newt, Triturus viridescens, and the label was found in the Schwann cell body, myelin,We use the terms myelin and myelin sheath synonymously, as generally employed in modern anatomical literature, for the array of packed Schwann cell wrappings around the axon of the peripheral nerve fiber. In biochemical literature the term myelin is used rather loosely sometimes to imply the chemical substratum of the myelin sheath or its lipoidal fraction. and axoplasm. Nerve separated by transection from its neuronal cell bodies was labeled about as densely as intact nerve. Moreover, pieces of nerve immersed in the isotope also incorporated the labeled molecule. These results have led us to reassess traditional views of the function of the sheaths surrounding the axon.
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  • 88
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    Notes: A morphological and histochemical investigation was conducted on the pronephros and mesonephros of the mouse embryo from 8.5 through 16.5 days. The pronephros appeared between days 8.5 and 9.5 as a thickening of the somatic layer of the intermediate cell mass. It consisted of three small clusters of cells on either side of the midline dorsally between the somite and the coelom, at the level of somites 8 and 9. The mesonephros arose during day 9 and persisted until day 16. In the male the anterior three tubules were incorporated into the testis at 15.5-16.5 days. The mesonephros consisted of approximately 11 tubules located between somites 10-17. The tubules possessed lumina and connected with the Wolffian duct. Indications of internal and external glomeruli were noted on day 11. The Wolffian duct reached the cloaca at ten days.Strong alkaline phosphatase activity was noted in the differentiating tubules. Cytoplasmic and luminal enzyme activity was observed between 9.3 and 12.5 days indicating possible function at this time. Acid phosphatase was demonstrable in the tubules and duct only on day 11. Ribonucleic acid was observed in the nuclei and cytoplasm of the mesodermal cells as they differentiated into tubules and duct. A decrease in RNA was noted after differentiation was complete. Periodic acid-Schiff material (diastase-stable) was localized in the basement membrane of the tubule and duct cells. A faint positive reaction was also found at the luminal border of the tubules. The strongest reaction was noted in the luminal border at 11.5-12.5 days. Those tubules being incorporated into the genital system in the male were also PAS positive. Morphological and histochemical evidence suggested that the mouse mesonephros, though quasi vestigial, may function for a short time.
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  • 89
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: Neural crest and dorsal neural tube of cervical and thoracolumbar levels were removed from embryos of Chelydra serpentina at stages ranging from 8 to 18 somites. Extirpation extended from the levels of the last four somites posteriorly around the neurenteric canal. Deficiencies in sensory and sympathetic ganglia occurred. Motor roots of the associated spinal nerves differentiated. In the absence of postganglionic neurons, the preganglionic fibers form a neuron-free plexus in the thoracolumbar region. Some observations in the cervical region indicate that the postganglionic neurons depend on preganglionic fibers for their differentiation. The cortex of the adrenal gland formed without related medulla in appropriate experiments.The normal morphology of the sympathetic trunks is illustrated. Superficial and deep cervical sympathetic trunks are described. The latter ascends the neck in a paravertebral position. Along its course are segmental ganglia and rami communicantes; it terminates by joining the medial branch of the superficial sympathetic trunk rostral to the ninth cranial nerve.
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  • 90
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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    Topics: Biology , Medicine
    Notes: The fine structure of the tunic of a typical ascidian was investigated because of the cellulose-like polysaccharide known to occur in its substance. The glycoprotein mantle does contain filaments very much like plant cellulose in morphology. Tunicin filaments are 35-50 Å in diameter, often beaded, and of indeterminate length. Histochemical evidence that they are composed of cellulose is given here and past chemical and physical studies on the unusual ascidian polysaccharide are reviewed. Moreover, we present here for the first time direct autoradiographic evidence that epidermal cells are involved in the synthesis and secretion of tunicin. Tritiated glucose is immediately incorporated into the Golgi zone of epidermal cells and labeled product appears in the tunic at later intervals. The fine structure of the epidermal cell is described in detail. Unlike the rather moribund appearing vanadocyte that wanders through the tunic, the epidermal cell has well-developed cytoplasmic organelles and a large vesicular nucleus. The granular endoplasmic reticulum is abundant and the Golgi complex is highly developed. It seems likely that the lamellae and vesicles of the Golgi complex are involved in the production of the tunic sugar and that tunic proteins of as yet unknown nature are produced by the ergastoplasm. Further investigation of the ascidian mantle should be of interest because of the possibility that cellulose is a more general component of glycoprotein surface coats in animals than has heretofore been recognized.
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  • 91
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    Journal of Morphology 121 (1967) 
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  • 92
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    Topics: Biology , Medicine
    Notes: Different types of sebaceous glands in guinea pigs were chosen to study their comparative responsiveness to steroid hormones. Glands selected were (1) Sebaceous glands associated with rudimentary hair in the supracaudal gland; (2) Free sebaceous glands of the nipple; (3) Sebaceous glands associated with the hair. The results showed distinct differences in sensitivity among these different sebaceous glands and according to the sex of the experimental animal. The most responsive of the glands in males was the supracaudal gland; in the female the most responsive glands were the sebaceous glands of the nipple. Sebaceous glands associated with normal hair were relatively insensitive to changes in hormonal level. In all cases testosterone propionate was more potent in stimulating any of the sebaceous glands than progesterone. After gonadectomy, various sebaceous glands showed unequal states of depletion due to the different rates of differentiation and disintegration of their cells into sebum.
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  • 93
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    Topics: Biology , Medicine
    Notes: The lymphoid cell population of thymus in the rattlesnake and king snake is similar to that of mammals. Lymphocytes occupy the interstices of an epithelial cell framework. An abudance of tonofilaments and desmosomes occupy the cytoplasm of epithelial cells with light, homogeneous nuclei and prominent nucleoli. Other epithelial cells contain phagocytized material in a dense cytoplasm which surrounds an irregular nucleus with heavily clumped chromatin. Small, granular vesicles are found within some epithelial cells.Myoid cells occur in the medullary area. In mature forms, myofibrils are arranged in a concentric fashion around the nucleus and occupy much of the cytoplasmic volume. The presence of developmental stages of these cells suggests their differentiation within the thymus of the adult animal.
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  • 94
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    Journal of Morphology 122 (1967) 
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  • 95
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    Journal of Morphology 122 (1967), S. 19-33 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ovary in Callosobruchus analis consists of telotrophic ovarioles with the so called nurse cells confined to one chamber at the anterior end of the ovariole. There are three types of lipids in the ovary: (1) L1 bodies that are present in the early oocytes, in the posterior prefollicular tissue and in the follicular epithelium and contain unsaturated phospholipids; (2) L2 bodies that have a complete or incomplete sheath of phospholipids and a triglyceride core; (3) L3 bodies that are formed of highly saturated triglycerides. Lipids are absent from the trophic tissue. In a mature oocyte the L1 and L2 bodies are cortical in distribution while the L3 bodies are centrally located.The mitochondria contain lipoproteins with RNA. The yolk spheres are acid mucopolysaccharides and protein in nature. The precursors of the yolk spheres appear first in the cortical coplasm and are absent from the follicular epithelium or the trophic tissue. The nucleolus of the oocyte shows evidence of extrusions that are believed to pass into the ooplasm.There are no nutritive cords connecting the trophic tissue to the oocytes; nor is there any evidence of any histochemically demonstrable nutritive material being contributed to the oocyte by the trophic tissue. The circumstantial evidence points towards a contribution of the raw materials to the oocyte by the haemolymph either through or in between the follicular epithelium in some soluble form or as submicroscopic particles.
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  • 96
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    Topics: Biology , Medicine
    Notes: Parenteral administration of methylcellulose causes massive splenomegaly and hemolytic anemia in rats. The red pulp of the spleen is markedly cellular due mainly to: (1) large numbers of voluminous free macrophages containing methylcellulose-induced vacuoles, (2) an increase in the number of plasma cells and (3) stasis of blood evidenced by a large number of erythrocytes and platelets in vessels, sinuses and cords. White pulp changes are usually less marked. Here the major change is the presence of macrophages containing methylcellulose-induced inclusions. The slow circulatory time in the spleen and the increase in macrophages may cause the hemolytic anemia observed in these animals.
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  • 97
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    Notes: The squirrel monkey uterine cervix was studied macroscopically and microscopically in intact and ovariectomized monkeys. The effect in ovariectomized monkeys of estradiol dipropionate or progesterone of both given after estrogen priming was studied by PAS staining.The lower portion of the cervix was dilated to form a vestibule into which projected fibromuscular colliculi which arose from the isthmic end of the cervix. The stratified squamous epithelium of the vagina was continuous through the external os with a similar epithelium lining the vestibule and covering the external surfaces of the colliculi. The transitional zone between the stratified epithelium and columnar cells was variable. The colliculi were covered internally with mucosal folds of columnar epithelium continuous with those of the endocervical canal.Glycogen concentration in the smooth muscle did not fluctuate markedly, irrespective of the hormones used. Glycogen granules were more numerous in the stratified squamous epithelium. Malt-diastase-resistant material appeared to be more abundant in the columnar epithelium and glandular lumina when the monkeys received both hormones than when they received solely estrogen or progesterone.
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  • 98
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  • 99
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    Journal of Morphology 122 (1967), S. 169-173 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histological examination of the fibrous and cellular connective tissue components of the periodontal ligament in the Caiman and the Alligator reveals the presence of reticular fibrillae, collagenic, elastic, and oxytalan fibers, as well as fibrocytes, osteoblasts, cementoblasts and epithelial rests. The oxytalan fibers differentiated by the peracetic acid aldehyde-fuchsin method are most numerous in the coronal region, radiating from the primary cementum into the periodontal ligament a short distance. Oxytalan fibers in fewer numbers are found interspersed between the oblique and the horizontal principal fiber bundles. Inasmuch as the crocodilian teeth have continuous replacement and thus a relatively short functional life, the oxytalan fibers of the Caiman and the Alligator appear to be proportionally fewer in number than they are in the mammalian periodontal tissues. The presence of the oxytalan fibers and epithelial rests in the Order Crocodilia (Crocodilia) adds to the number of dental structures shared with the Class Mammalia (Mammalia) (mammals) such as a stellate reticulum, a primary and secondary cementum and a periodontal ligament. This furnishes additional histological evidence for evaluation of the phylogenetic position of this group.
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  • 100
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histochemical methods, especially azo dye methods for detecting acid phosphomonoesterase activity were applied to normal, regenerating and denervated, amputated limbs from larval Amblystoma maculatum. Efforts were made to control inactivation of enzymic activity and diffusion of both enzyme and reaction product. “Base-line” values for enzymic activity were determined for normal limbs. Activity appeared most intense in macrophages, less intense in epidermis and cartilage matrix. Some activity was detected in Schwann cells, peri- and endoneurium and muscle fibers form normal limbs. Enzymic activity in regenerating limbs was strongest within macrophages which appeared in increased numbers especially in early stages. Wound tissue showed little increased activity. As the blastema formed, increased enzymic activity was detected in epidermis and within increased numbers of macrophages. Chondrocytes showed increased activity especially during cartilage matrix deposition. Amputated, denervated limbs showed large numbers of active macrophages beneath and within epidermis and along muscle. As regression commenced, areas of cartilage matrix breakdown showed increased enzymic activity but, in general, greatest activity was in macrophages. The various possible roles of acid phosphomonoesterase activity in the specific biological situations dealt with are considered in light of such observations.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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