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  • 1965-1969  (439)
  • 1940-1944
  • 1966  (439)
  • Life and Medical Sciences  (439)
  • 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
    Additional Material: 10 Ill.
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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
    Type of Medium: Electronic Resource
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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.
    Additional Material: 18 Ill.
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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
    Electronic Resource
    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.
    Additional Material: 11 Ill.
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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.
    Additional Material: 8 Ill.
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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
    Electronic Resource
    Electronic Resource
    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
    Electronic Resource
    Electronic Resource
    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
    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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  • 24
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    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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  • 25
    ISSN: 0362-2525
    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%.
    Additional Material: 23 Ill.
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  • 26
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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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  • 27
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    New York, NY : Wiley-Blackwell
    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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  • 28
    ISSN: 0362-2525
    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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  • 29
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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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  • 30
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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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  • 31
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    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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  • 32
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    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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  • 33
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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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  • 34
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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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  • 35
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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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  • 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 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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  • 37
    ISSN: 0362-2525
    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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  • 38
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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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  • 39
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    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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  • 40
    ISSN: 0362-2525
    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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  • 41
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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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  • 42
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    Journal of Morphology 119 (1966), S. 425-433 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nucleoli of 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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  • 43
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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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  • 44
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    Journal of Morphology 120 (1966), S. 233-265 
    ISSN: 0362-2525
    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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  • 45
    ISSN: 0362-2525
    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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  • 46
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    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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  • 47
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    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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  • 48
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    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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  • 49
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    Journal of Morphology 118 (1966), S. 1-9 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of low temperature on embryonic induction were investigated. Presumptive epidermis cells of Rana pipiens were either pretreated with cold (4°C) and then treated with lithium chloride at the same temperature, or activated by lithium chloride at 22°C, then rapidly chilled to 4° and kept at this temperature for a period of time. Cultures were made from the treated cells.It was found that induction at low temperature could occur, although it did not proceed beyond determining neuralization. When, on the other hand, the cells were first induced with LiCl to the point at which they should have been determined to differentiate into melanophores, but were then rapidly chilled and kept in the cold for some time, the effects of induction were suppressed and the cells differentiated into ciliated epithelium. A 15-60 minute lag in time between induction and chilling (during which the cells were kept in the culture medium at room temperature) allowed neural induction to be gradually “fixed,” and a 120-180 minute lag was sufficient for melanphore induction to become insensitive to the subsequent treatment with cold.It is speculated from these results that induction occurs very slowly at low temperature and that the inductive stimulus activates a sequence of reactions, one or several of which are strongly repressed by the cold. In this case, when no products result from these reactions, the sequence is assumed to stop and possible feed-back mechanisms switch the whole system to its initial condition.
    Additional Material: 8 Ill.
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  • 50
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The most intense and widely distributed sudanophilic responses of cryostat-sectioned newt limb tissues were obtained with a simultaneous fix and stain procedure of 1:1 10% formal-calcium and sudan black B. Droplets and globules of lipid mixtures and rodlets (mitochondria) were typical responses distributed within the epidermis, subcutaneous glands, dermis and other connective tissues, striated muscle (also with positive fibrils), tunics of blood vessels, and blood cells. A prominent droplet response was located subjacent to the adepidermal basement membrane. The myelin of brachial nerve stained intensely.In regenerating limbs, the wound epithelium response was comparable to that of epidermis. Post-amputational lipophanerosis of injured muscle and brachial nerves was observed. The retrograde degeneration of nerve myelin was extensive, and continued into the early differentiative phase of regeneration. Lipid-engorged macrophages were prominent among the injured tissues, distal to these, and within the wound epithelium.The regeneration blastema revealed a large quantity of sudanophilic lipid. Prominent droplet and rodlet responses were typical of the myelinating regenerating nerves. The response of regenerating muscle equaled that of the mature stump fibers. The cells of the regenerating chondroskeleton contained sudanophilic lipid.Organic solvents such as acetone, ether, chloroform and chloroform:methanol reduced or prevented the sudanophilic responses. Sudan red 7B revealed less lipid than did sudan black B. A fixation effect was demonstrated with post-chromated formalcalcium, and chromic-formalin fixed sections. In the latter preparations, swollen-bodies, identified as mitochondria, stained intensely.
    Additional Material: 10 Ill.
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  • 51
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Alpha and beta cells can be distinguished by differences in mitochondrial and secretion granule structure. Many mitochondria of alpha cells possess “tubular” or prismatic cristae oriented longitudinally and having triangular profiles in cross-section. The matrix is particulate, with the roughly spherical particles measuring about 100 A in diameter. Evidence is presented indicating that alpha and beta granules are sequestrated in association with Golgi elements. Fully-condensed beta granules, assumed to be insulin, appear homogeneously dense and crystalline. Recurrent profiles of crystalline beta granules suggest that they possess an octahedral configuration. Alpha cell granules also appear homogeneously dense but have round profiles.Many acinar cell nuclei in both normal and alloxan-treated pancreata display masses of moderately dense fibrils oriented roughly parallel to each other. These fibrils are about 200 A across and their terminal portions are rebranched and often appear to be continuous with the finely granular or filamentous component of the nucleoplasm. Not infrequently the fibrils show evidence of periodicity.Alloxan has a specific destructive effect on beta cells. An initial effect seems to be the disruption and coalescence of the bounding membranes of beta granules. Lysosome-like bodies are often seen in beta cell cytoplasm, which ultimately becomes degranulated and necrotic following prolonged administration of large doses of alloxan.
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  • 52
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The vessels of the forelimb stump and regenerate were perfused with Prussian blue and studied as whole mounts and in histological sections to reveal the condition and disposition of the blood vessels in various stages of forelimb regeneration in the adult newt, Triturus viridescens. The development of the vessels in the regenerate seemed to be comparable in all its essential features to that which has been described for the normal developing limb in urodele, chick and pig embryos.The first signs of regeneration of the vessels are seen during wound healing when fine sprouts appear from the old vessels near the amputation wound. These grow and anastomose, but are limited to the transition region between old and new tissues and avoid the growing blastema during the early stages of regeneration. As the regenerate enlarges into a conical structure vessels invade the proximal part of the growth and avoid the distal regions. It is only during the stages of histogenesis and morphogenesis that vessels grow into more distal regions. The regions of most active enlargement of the early or later regenerate are those most poorly vascularized. These results are discussed against the background of the activity of certain enzymes during regeneration. In the advanced regenerate, preferential channels are consolidated until in the palette and digital stages the pattern of the blood vessels resembles that of the normal limb.
    Additional Material: 15 Ill.
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  • 53
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 119-135 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy of the femoral glands in an iguanid lizard, Crotaphytus collaris collaris (Say), is described. The 48 lizards (including three embryos) from which glands were examined were obtained throughout their season of activity at one locality in Kansas.In animals of both sexes the glands lie in a linear series on the ventral aspect of each thigh. They are composed of branching tubes and tubules of epidermal and dermal origin. The row of femoral pores is the only external manifestation of the glands.Post hatching, the glands of males increase in size and complexity; little onto-genetic change occurs in the glands of females.The relative length of the glands appears to vary seasonally in adult males suggesting variation in their activity. The greatest relative sizes occur in the breeding season.At times a stratum corneum, continuous with the stratum corneum of the skin, occurs in the duct of the gland internal to part of the secretion plug. Formation of the stratum corneum seems to be initiated in the autumn prior to hibernation, and the stratum corneum removes the outer part of the secretion plug in the next ecdysis; meanwhile, production of a new secretion plug is initiated.The anatomy of the femoral glands in Crotaphytus is similar to that of the described glands of other species of lizards.
    Additional Material: 3 Ill.
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  • 54
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 55
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 137-147 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development of the centrum and the notochordal (intravertebral) cartilage in Hypogeophis is described. The notochordal cartilage is produced in each vertebra by certain areas of the notochordal epithelium and there is no indication of the invasion of the notochordal sheath by mesenchyme cells. The bands of cartilage are of constant occurrence and persist in the adult vertebrae.The vertebrae are autocentral and the centrum is produced (independently of the neural arches) by a tube of circumnotochordal mesenchyme cells.
    Additional Material: 4 Ill.
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  • 56
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 118 (1966), S. 149-165 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hatching eggs from inbred lines of chickens (inbreeding coefficient exceeds 95%) which show various degrees of resistance and susceptibility to Rous sarcoma, were used for experimentation. Adult tissues were grafted onto the chorioallantois on the tenth day of incubation and tissues of host and control embryos were harvested on the twentieth day of incubation. Enzymes were localized in tissues by histochemical procedures.Small pieces of tissue (thymus or bursa), when grafted onto the chorioallantois, increased the size of the spleen in host embryos although splenomegaly did not invariably occur. Two types of reactions were observed in the spleen, i.e., enlarged spleens with cysts or enlarged spleens which from a morphological point of view were normal. Grafts of either thymus or bursa decreased the size of the host embryo's bursa or were without effect. When weight of the bursa of host embryos was significantly less than that of control embryos on the twentieth day of incubation, this size relationship persisted in chicks four weeks post hatching.Intensity of dehydrogenase and acid phosphatase reactions in cysts of enlarged spleens and in the multinucleated giant cells investing them suggests that they consist of groups of degenerating cells. Intensity of enzyme reaction indicates that enlarged spleens of host embryos in which cysts were absent were normal. Enzyme reactions in the bursae of experimental embryos were more intense than those identified in the same tissues of control embryos. Catabolic reactions were the predominant type in grafts ten days subsequent to implantation. Grafts increased the number of erythrocytes in the peripheral blood of host embryos.
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  • 57
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myocytes are long, fusiform cells found in the osculum and other contractile areas of many sponges. Myocytes in the oscular sphincter of Tedania ignis and the osculum and dermal membrane of Microciona prolifera were studied with light- and electron-microscopes to compare their structure to that of muscles. Salient points of similarity between myocytes and smooth muscles were their long, fusiform shape, their red color after staining with Mallory's triple stain, and the presence of filaments running longitudinally in the cytoplasm.Microciona myocytes have thick filaments of 150-250 Å diameter and thin filament of 50-70 Å diameter, and in transverse sections the thin filaments occasionally appear as a ring of dots around a thick filament. Longitudinal sections of Tedania myocytes show only one type of filament, which varies from 100 Å to 200-300 Å diameter in thick regions of the filament. Although transverse sections show light material around the dense filaments, a distinct pattern of thick and thin filaments is not seen in Tedania.Due to infrequent contacts between cells, the large extra-cellular space observed with the electron microscope (49% in Tedania, 57% in Microciona), and the absence of nerves, each myocyte probably acts as an independent contractile unit.
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  • 58
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Subnormal growth in length and diameter of the duodenum is encountered both in chick embryos injected with thiourea at 11 days of incubation, and in embryos injected with cortisone acetate at 14 days of incubation. Morphogenesis of previllous ridges and villi is retarded in thiourea-treated embryos. Morphogenesis of previllous ridges and villi in cortisone acetate-treated embryos at first seems to be slightly accelerated over that of controls, but the acceleration does not appear to be maintained, and the hormone may actually be inhibitory to normal morphogenesis of villi by 19 days of incubation. The results indicate that normal levels of endogenous thyroxine are necessary for normal growth in length and diameter of the duodenum and for normal morphogenesis of previllous ridges and villi. The possibility that adrenocorticoids may also play a role in the normal development of these parameters is indicated, although the evidence is inconclusive.
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  • 59
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A survey of the comparative morphology and histology of the twelve glands in the ophidian head was made. The nasal and Harderian glands are the only non-oral glands. The premaxillary, supralabial, posterior, Duvernoy's and venom glands are serially homologous. The infralabial, sublingual and supralingual glands are not related to the other oral glands. The relationships of the temporomandibular and anterior temporal glands to the other oral glands could not be determined.For each gland a synonymy of previously used names, its approximate location within the head and its distribution within the various groups of the Ophidia is given. The general histological picture of most of the glands is illustrated and available information on their embryology and innervation is summarized.
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  • 60
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Lipids tightly bound to cell and tissue proteins (lipoproteins) were investigated with the acetone-sudan procedure in cryostat-cut sections of normal and regenerating limb tissues of the adult newt, Diemictylus viridescens.Nuclear and cytolplasmic membranes of all tissues stained moderately black; the nucleo- and cytoplasm stained less intensely than their membranes. Connective tissue fibers of the dermis, mysial and neural sheaths, and tunics of blood vessels yielded intense responses. In striated muscle of the limb, myofibrils and associated striations responded strongly. Nerve myelin responded weakly.In the preblastemic regenerate, the fibrous adepidermal basement membrane terminated abruptly at the surface of amputation. A distal fibrocellular residue was evident in continuity with the retrograde degeneration of amputation-injured muscle: observations suggest a possible contribution to the fibrocellular reticulum from myofibrils. The regeneration blastema appears isolated from proximal limb tissues by the intervening fibrocellular reticulum. The response of the blastema cell is relatively weaker than that of other cells and tissues. Regenerating muscle is recognized by the appearance of prominently stained myofibrils in myoblastic extensions off the limb stump musculature. The matrix and chondrocytes of regenerating cartilage stain for lipoprotein, with the osteoid of osteogenic centers responding strongly.Polychrome responses were obtained from hyalin-bodies within interphase nuclei, and from chromosomes in mitosis, suggesting that chromosomal lipid has been stained.Supporting the lipidic character of the observed responses is the negative reaction following long term lipid extraction in warm chloroform: methanol.
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  • 61
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The electric organs (main, Sachs' and Hunter's) of a 23 cm and a 38 cm long Electrophorus electricus were studied by histological methods. The results were compared with 12 cm (Keynes, '61) and 140 cm (Couceiro and Ackermann, '48) specimens. All three electric organs originate from striated muscle fiber as indicated by the presence of a striated structure in the undeveloped electroplates. The three organs do not develop simultaneously but in succession: first Sachs' organ, then the main organ and finally Hunter's organ, with considerable overlap in time. In all three cases, the anterior extremity of the organ develops last. The classical notion that the main organ originates from the lateralis imus muscle is not supported by the present findings.
    Additional Material: 5 Ill.
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  • 62
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 155 (1966), S. 139-140 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 63
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Distribution of cholinesterase within the sinus node, AV node and His bundle of the human heart was studied utilizing acetylthiocholine as the substrate. Cholinesterase is present in large amounts in the conduction system tissue, much smaller amounts in right atrial myocardium and was not observed in ventricular myocardium. The sinus node artery was devoid of cholinesterase, as was the sarcolemma and nucleus of cells in the conduction system. Cholinergic nerve endings stained the most heavily of all tissue studied and were more numerous in the sinus node than the AV node. Stellate-shaped cells previously suggested to be the pace-making site in the sinus node were found to contain abundant cholinesterase. Fibers in the AV nodal bypass tract, which lies between the AV node and right atrial endocardium, also contain cholinesterase. Within individual cells of the sinus node cholinesterase could be identified within myofibrils, with periodic absence in the linear staining most likely corresponding to the Z bands. Other organelles within the cells also contained cholinesterase, but their precise definition was impossible with the present technics. Possible functional significance of these histochemical observations were discussed.
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  • 64
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Although the role of the goblet cell in mucous secretion has been known since 1837, the actual process by which mucous is formed by the cell still is open to question. There is a known proliferation of the Golgi membranes during the early formation of mucous within peripheral Golgi vacuoles. However, there also is a concomitant proliferation of rough-surfaced endoplasmic reticulum which contains an electron dense material within the lamellae. It is suggested that the endoplasmic reticulum synthesizes a protein moiety which is transported to the Golgi apparatus. There the protein is combined with acid mucopolysaccharides and glycoproteins, that are synthesized by the Golgi apparatus, to form the mucous droplets visible in the electron microscope.Examination of intestinal goblet cells of man, rat, and guinea pig, after stimulation of the cells to evacuate their mucous, also reveals a basic fine structure that clearly is distinguishable from the fine structure of columnar absorbing cells.
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  • 65
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A time study of the incorporation of tritiated thymidine into the thymus of Fischer rats ranging from 15 days to one year of age has been made. The data obtained from both autoradiographic and histological analyses indicate that the mitotic activity in the thymus of young animals is much higher than in old animals. The medium thymocyte, by virtue of its higher relative proliferative capacity, is responsible for the greater portion of cellular production during the intense pre-pubertal growth phase of the thymus. A decrease in proliferative capacity of medium thymocytes occurs between 60 and 90 days of age, which appears to initiate the onset of age involution of the thymus. The data further indicate that small thymocytes are cells which do not undergo division.
    Additional Material: 20 Ill.
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  • 66
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 154 (1966) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 67
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 154 (1966), S. 705-711 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In stages H18-H22 the neural tube was composed of a partially stratified epithelium, reflecting its origin from epidermal and sensory layers of ectoderm. Mitotic figures were distributed over the whole neural wall. Fifty-four to 91% were peripheral to the luminal zone. There was no evidence of nuclear migration attending mitosis. After integration of epidermal and sensory cells into a single epithelium by stage H24, mitotic figures were mostly near the lumen and for some time prophase stages were distributed peripherally. During this period nuclear migration to and from the lumen accompanied mitosis as in higher vertebrates. By stage H46 nuclei of the neural epithelium were restricted to a narrow zone near the lumen. Most mitotic figures and all other phases of mitosis were in this zone. There was a consequent lack of appreciable nuclear migration. A few peripheral mitotic figures remained in neural cells through stage H46. Some were in epithelial cells whose nuclei did not migrate to the lumen. Others were in the mantle zone, perhaps in neuroblasts. These observations support the view that the neural epithelium, whatever its extent, is germinal. Neither a “germinal zone” nor a special strain of “germinal cells” could be distinguished at any stage.
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  • 68
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Observations were made on the pre- and postnatal development of the photoreceptors in the central region of the retina in the diurnal rhesus monkey. Histologic findings on the level of development of the retina at birth revealed a macula with the characteristic adult foveal depression. Observations on the ultrastructural development of the receptor inner and outer segments revealed that the photoreceptors were well differentiated even at birth. An evaluation of the prenatal morphogenesis of the photoreceptors indicated that the initial differentiation may take place as early as 100-125 days after conception. At 100 days after conception, the pigment epithelium consisted of a single layer of cuboidal cells with cytoplasmic content of smooth endoplasmic reticulum, but was only sparsely populated with mitochondria and rough endoplasmic reticulum. The photoreceptor inner segments contained vesiculation in the supranuclear region, while the incipient outer segments consisted of outbudding ciliary processes. By 125 days postconception, the pigment epithelium contained such cytoplasmic specializations as increases in rough endoplasmic reticulum and mitochondria, as well as greater organelle complexity. In the photoreceptor outer segments there were arrays of closed bimembranous discs, with vesiculation at the apical tip in the inner segments. A comparison of the pre- and postnatal ultrastructural changes in the choroid and the interstitial zone comprising the photoreceptor outer segments and the cell processes of the pigment epithelium suggested that the changes in these areas represent a critical aspect in the maturation of the retina.
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  • 69
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Lymphocytes with “atypical nuclei” have been shown to increase in lymph nodes during afferent drainage ('64). This report concerns the selective staining of these nuclei with the MBL technique (exposure of methylene blue stained sections to alcoholic Lugol's solution).Comparisons with other techniques, together with suitable extractive procedures, lead to the conclusion that chromatin throughout the hematogenous series of lymphocytes is subject to two general forms of selective response to the MBL technique during lymphatic drainage. These are distinguished by differences in: 1, time required for staining with the iodine solution; 2, morphology; and 3, ease of dedifferentiation.The first response (unpatterned, coarse, intranuclear granules) occurs in older hematogenous lymphocytes only, after brief exposures, and varies in ease of dedifferentiation.The second response (intranuclear, reticulated figures) occurs in hematogenous lymphocytes of any age, after long exposures to iodine, and is slow to dedifferentiate. The figures uniformly conform to the reticular patterns of inter- and prophase, and become condensed as cell volumes decrease.The findings show that fluctuant, dynamic relationships exist among hematogenous lymphocytes in nodes :- unidentified factors become associated with their chromatin and result in selective nuclear staining; the chromatin becomes restricted to reticular positions and mitoses cease; cell volumes shrink progressively; nucleo-cytoplasmic ratios increase; and intranuclear structures become condensed. Yet evidences of degeneration are not found.
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  • 70
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The tough, fibrous resilient, acellular capsule (chorion) of fish embryos has been characterized as protein-keratin-like in composition. It has resisted digestion by common proteinases, such as trypsin, chymotrypsin, pepsin, and papain. We have been able to remove the chorion with pronase, a commercially available (Calbiochem) proteolytic enzyme of bacterial origin with broad substrate specificity.The enzyme at concentrations of between 0.5 and 0.00625% was tested at room temperatures in several Ca++ and Mg++-free solutions including a weak salt solution (0.1% NaCl), Yamamoto solution (0.7% NaCl), and distilled water with either phosphate or Tris buffer at pH 6.0-11.5. The embryos were in their first day of development at the start of the treatment.It was found that the enzyme was most effective in Tris-buffered water, less so in weak salt solution and least effective in Yamamoto solution. Phosphate buffer caused some precipitation of the enzyme. The chorion was thinned over a wide range of pH (7.0-11.0) and in concentrations of enzyme between 0.5-0.0125% within 21-36 hours. Although the embryos frequently escaped from the thinned chorion by rhythmical movements, many of the embryos could be removed easily with the aid of common forceps. Once removed from the chorion the embryos were placed in phosphate buffered weak salt solution (Rugh), where, with few exceptions, they developed normally.Considering least mortality and highest yield of embryos with maximally thinned chorions, Tris-buffered distilled water at pH 9.5 or 10.0 in an enzyme concentration of 0.025% was found to be optimal. Under these conditions 78% of the total number of embryos treated had completely thinned chorions within 24 hours.
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  • 71
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Electron micrographs of rat gastrocnemius muscle fibers show membrane-like dense structures traversing the space between the transverse system (T) and the terminal segments of sarcoplasmic reticulum (R). The periodicity of the structures, viewed in longitudinal sections of triads, varies from 150-250 Å. The distance between apposed membranes of T and R is 80-100 Å at the level of the dense structures between T and R. The distance is slightly greater than 100 Å at the level of less dense areas which alternate with the dense structures. The scalloped appearance of the R membrane, associated with differences in distance between T and R when the levels of dense structures and less dense areas are compared, leads to the suggestion that a holding force might be exerted by the dense structures. Such a holding force would support the view that the membrane-like dense structures are indeed connections between T and R. If membrane-like connections between T and R completely surround the less dense areas it is possible that a “physiological tight junction” conductive to electrotonic spread of current might exist between apposed membranes of T and R.
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  • 72
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: By combining the histochemical fluorescence method for catecholamines (CA) and 5-hydroxytryptamine (5-HT) with electron microscopy it has been possible to study the ultrastructure of the central CA and 5-HT nerve cells of the locus coeruleus and the nuc. raphe dorsalis. The CA and the 5-HT nerve cells have the same ultrastructural characteristics: a well-developed granular reticulum and a peri-nuclearly situated, prominent Golgi apparatus which almost completely surrounds the nucleus. Agranular vesicles (300-500 Å in diameter) are found mainly in a perinuclear area in association with the Golgi apparatus. They are similar to the small agranular vesicles present in large numbers in the presynaptic bags. A few complex vesicles and granular vesicles (600-1200 Å in diameter) are noticed throughout the cytoplasm. No certain changes are observed in the different types of vesicles after treatment with reserpine or MAO inhibitors.It is suggested that the agranular vesicles contain CA, since these vesicles are most numerous in a perinuclear area where the concentration of the amines are highest. In spite of the low number of agranular vesicles present as compared to the high number found in nerve terminals they might store at least a considerable part of the amines, since the amine concentrations are much lower (100-1000 X) in the nerve cells than in the terminals.
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  • 73
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The results of autoplastic and homoplastic transplants of PET mouse tissues indicate that the state of differentiation of the developing muscles limits the extent of invasion by pigment cells of the muscles of the leg in PET mice. Additionally, intracoelomic grafts into host chick embryos of PET mouse leg tissues has given evidence which suggests that the pigment cell behavior is affected also by a restriction of pigment cell proliferation and concurrent migration by the initiation of pigment cell morphogenesis. Thus it appears that the colonization of the leg muscles by pigment cells in the PET mouse is governed both by the structural limitations and morphogenetic influence imposed upon the melanoblasts by the tissue substrate.
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  • 74
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    The @Anatomical Record 155 (1966), S. 117-132 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Thymic reticular cells of the guinea pig were studied at different stages of its development and involution: the fetus of the last third of pregnancy, the newborn, the puberal adult and the adult implanted with estradiol.Most of the reticular cells were epithelial with desmosomes and tonofilaments originating from the endodermic primordium. In the medulla, some of these epithelial cells appeared to be transformed into elements of Hassall's corpuscles with an increase of tonofilaments in close association with keratohyalin granules.Moreover, phagocytic reticular cells were occasionally seen. Their origin remains unknown (epithelial or menschymal ?).The problem of the thymic secretion is discussed. There was no convincing evidence of a secretion of protein or polypeptid inside these reticular cells whatever the age of the animal. However, it is not possible to exclude the presence of another form of endocrin secretion, especially a colloid or a steroid secretion, at least in the fetus and newborn thymus.
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  • 75
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 156 (1966), S. 67-81 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The effects of acute stretch, laterally applied pressure, and exterfusal contraction upon the morphology of spindles in cat muscles have been studied by making measurements from serial histological sections. Cross-sectional areas of bag and chain intrafusal fibers were taken and the circumferences of spindle capsules measured at the equatoriallevel. From these area values the relative effects on length of the measured structures were inferred. 1. Stretch was found to lengthen the capsules and both bag and chain fibers. 2. Contracture induced by use of the drug ryanodine was accompanied by shortening of both bag and chain fibers. 3. Stretch was still effective in the presence of full contracture. 4. Pressure applied to the lateral surface of the muscle affectedboth bag and chain fibers.These findings taken with other considerations demonstrate the anatomical basis for the mechanism that is commonly assumed to cause the acceleration in discharge from primary and secondary endings with stretch and the “pause” with contraction of the gross muscle. The relation to a possible pressure sensing mechanism for secondary endings is discussed.
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  • 76
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Little has been reported concerning circulus arteriosus cerebri in adult rats. A study of rats' brains perfused with latex and fixed in formalin revealed the general configuration of a circular type pattern of the major cerebral arteries in which all vessels were patent. No major vessel was “string-like” and no circles were incomplete.Certain morphological features not described previously were observed. Included among the more significant of these were: (1) the asymmetrical origin of the posterior cerebral artery found to occur in more than half of the animals; (2) the presence of cleft-like buttonhole formations along the anterior cerebral artery of one or both sides, a feature that was practically species characteristic; (3) the occasional presence of an anterior communicating artery supplemental to the commonly occurring side to side fusion of the two anterior cerebral arteries. Two animals, possessing two anterior communicating arteries connecting otherwise unfused anterior cerebral arteries, were exceptional; (4) an olfactory artery to the nasal cavity branched promineantly from the anterior cerebral artery in all animals.Before exiting from the cranial cavity through the dorsomedial cribriform foramen, the olfactory artery gave origin to a laterally directedramus, the central cribriform artery, that passed through the central cribriform foramen into the nasal cavity.
    Additional Material: 12 Ill.
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  • 77
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    The @Anatomical Record 156 (1966) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 78
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    The @Anatomical Record 156 (1966), S. 157-173 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Microcirculation of rat livers was studied on preparations perfused with silicone rubber. Silicone rubber provided an excellent perfusion medium for the study of the special arrangement of hepatic microcirculation.As demonstrated by Gershbein and Elias ('54), a great portion of the hepatic venous tree of the rat liver receives sinusoidal channels and thus this portion is located centrilobularly.In the portal venous system of the rat liver, not only the distributing veins but also the conducting veins give rise to inlet venules regularly to adjacent peripheral sinusoids.Rich capillary networks of the periductal plexus which receive their afferent channels from the hepatic arteries and empty their blood either into the portion veins or into the adjacent peripheral sinusoids are demonstrated in the portal canals. Less prominent fine capillaries are distributed in the walls of portal veins and in the connective tissue components of larger portal canals. Existence of a more direct type of anastomoses between the hepatic arteries and portal veins through capillary networks in the medium and large sized portal canals is also indicated. Evidence for the existence of intralobular arteriolar terminals were not obtained and the present observation indicated that the hepatic arteries terminate at the periphery of the lobule.
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  • 79
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    The @Anatomical Record 156 (1966), S. 215-227 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The “cell web,” a supporting fibrillar component of the cytoplasm was investigated in sections of adult rat kidney stained with the tannic acid-phosphomolybdic acid-amido black (TPA) technique. At the apex of all tubular epithelial cells and immediately below the brush border of microvilli, the cell web formed a thin layer of tightly knit fibrils which inserted on terminal bars, the latter following a straight or sinuous course in circumscribing the cell apices. On the lateral surfaces of all tubular cells, with the exception of those lining the first segment of the proximal convoluted tubule and the whole distal convoluted tubule, some TPA stained fibrils were seen running from the terminal bars toward the base of the cells. Lastly, at the base of all tubular cells, excepting those of the macula densa and the cortical and papillary collecting ducts, some coarse fibrils, oriented circularly around the tubule, were seen close to the basement membrane.Thus, in most tubular epithelial cells, cell web fibrils were found below the apical, lateral and basal cell surfaces, making up a framework for the support of the cytoplasm. Cell Web fibrils were also observed in the parietal and visceral epithelial cells of Bowman's capsule.
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  • 80
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 156 (1966) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 81
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    The @Anatomical Record 156 (1966), S. 253-267 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The appearance of Brunner's glands in the rat, before and after feeding, has been examined with the electron microscope. The glands are arranged in the duodenal submucosa in aggregates of coiled tubules which open into the bases of the crypts of Lieberkühn. Component cells appear to be more mucous than serous. The basal cytoplasm contains some granular endoplasmic reticulum, numerous free ribosomes and mitochondria. Multiple Golgi elements lie in relation to the nucleus and the apical cytoplasm contains varying concentrations of pale secretory droplets which show a tendency to fuse into complexes. Scattered between the large secretory droplets are numerous small vesicles, also considered to contain a secretory product.The cytological features are discussed in relation to previous observations on Brunner's glands in other species. It is apparent that there are considerable species differences. However, in all species it appears likely that the complex secretory materials are elaborated principally by the ergastoplasm.
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  • 82
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    The @Anatomical Record 155 (1966) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 83
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Trunk and tail parts from larvae of Triturus virdescens were implanted into pockets made in the trunk epaxial musculature of adult animals of the same species. Histological observations were made on these grafts at intervals up to 60 days and at eight months following implantation. During the first few days after implantation the small, fragile grafts were distorted and compressed by the mechanical restrictions of host tissues, but they began to increase in size and rigidity by 20 days and eventually some reached sizes that exceeded considerably those of equivalent trunk and tail parts in intact control larvae. Differential responses to the host environment were seen among the various tissues of the grafts. As growth proceeded, the proportion of cartilage and bone relative to the other tissues increased. Gut, gut derivatives, nerve cord, and kidney showed initial growth but usually underwent later degenerative changes and declined in relative mass. Muscle and connective tissue did not show degenerative changes but did not increase significantly in mass. Limb-like protuberances and (in a single graft) a mass of well differentiated testicular tissue were seen. No metastases or infiltrating growths occurred.
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  • 84
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A volume-distribution analysis of the water soluble contrast medium, meglumine iothalamate, injected into various ventricular and subarachnoid sites was accomplished radiographically in the cat with the aid of a newly designed screw-type cannula having a deadspace of 6 to 8 m̈l. The cannula is positioned stereotaxically and mounts directly and permanently in the cranium by a single self-tapping insertion maneuver. As little as 100 m̈l of solution injected into the anterior horn of the lateral ventricle, or 50 and 20 m̈l into the third and fourth ventricles, respectively, was visualized immediately in the lateral apertures of the fourth ventricle connecting with the subarachnoid spaces. Injection of 50 m̈l into the posterior horn of the lateral ventricle delineated the entire ventricle as well as the interventricular foramen. A volume of 12 m̈l deposited in the base of the third ventricle served to define the hypothalamic cleft and infundibular recess. If rate of injection was not excessive, the solution could be introduced into the third and fourth ventricles without penetrating into the more anterior regions. Radiopaque medium injected into subarachnoid spaces (cisternae ambiens and cerebellomedullaris) did not enter the ventricular system.
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  • 85
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    The @Anatomical Record 154 (1966) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 86
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    The @Anatomical Record 154 (1966), S. 41-71 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: To find out whether or not mammalian cells have a surface coat, over 50 cell types were examined in rat tissues stained with the periodic acid-Schiff technique for glycoproteins or the colloidal iron technique for acidic carbohydrates.With both techniques, nearly all cells investigated are outlined by a thin, but definite band of stained material, indicating the existence of a surface layer. The surface layer is uniform in leucocytes, fibrocytes and other cells of mesenchymal origin. This is true in neurons too, although associated structures may also be stained. In simple epithelia, the layer appears thicker at apical than at lateral and basal surfaces. (At the basal surface, the layer separates the cell from the basement membrane, which is itself colloidal iron negative and therefore is not part of the cell coat.) Finally, the layer is usually interrupted at the tight junction of terminal bars (where the cell interspace disappears as the plasma membranes of adjacent cells fuse). This finding confirms that the layer is not part of the plasma membrane itself but is a surface ‘cell coat.’In agreement with biochemical data, the staining properties indicate the presence of glycoprotein(s) and acidic residues in the coat of rat cells.
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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: Medicine
    Notes: The appendices and tonsils iliaca of 198 embryonic and neonatal rabbits between 26 days of gestation and 18 days after birth have been examined. Special cytological and histochemical techniques and light and phase microscopy have been employed in order to determine the origin of the lymphocytes in these lympho-epithelial organs.Sequential developmental and cytological changes in the appendices and tonsils iliaca of the embryonic and neonatal rabbit indicate that the first lymphocytes are of small and medium size and appear by the twenty-ninth day of development, viz., two to three days prior to birth. Lymphoblasts are not evident until a short time after birth when the lymphocytic nature of these organs has been established. The first lymphocytes in the appendix and tonsil iliaca appear to develop in situ by the direct transformation of reticular or mesenchymal cells. Lymphocytes tend to migrate toward the mesenchymal condensation of the so-called domed elevations of the appendix and tonsil iliaca or remain in the connective tissue beneath these domed structures. In addition, lymphocytes enter the appendix and tonsil iliaca via the blood stream at or immediately after birth. These lymphocytes intermix with other lymphocytes in these organs and undergo proliferation within the lamina propria and developing lymphocytic nodules.Morphological evidence strongly suggests a dual origin or source of the lymphocytes in the developing appendix and tonsil iliaca of the rabbit; a population of lymphocytes derived originally from reticular cells and a population of lymphocytes derived extra-appendiceally possibly of thymic (epithelial) origin. Neither the origin of lymphocytes or lymphocytic precursors from appendiceal epithelial cells nor the derivation of lymphocytic nodules from appendiceal crypts could be substantiated in this investigation. The mode of origin of lymphocytes and subsequent manner of lymphocytic development in the appendix and tonsil iliaca of the embryonic and neonatal rabbit differ markedly from that observed in the embryonic thymus and bursa of Fabricius.
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  • 88
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The epidermal melanocytes which, except in the ears, face and friction surfaces, are normally nonmelanotic become gradually DOPA positive and melanogenic after exposures to ultraviolet light. Peak melanogenic activity is attained after 23 exposures (over a one-month period). With continued treatment, however, both DOPA positivity and melanogenic activity decline. After 46 exposures (over a two-month period) the population of DOPA positive melanocytes is about one-half of that found after 23 exposures. The population of Langerhans cells, normally high in untreated skin, drops steadily as the melanocytes become melanogenic. When, after 46 exposures, the active melanocyte population drops, that of the Langerhans cells rises. There is, thus, an inverse relation between melanocyte activity and the number of Langerhans cells.
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  • 89
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Accurate determination of the neuron populations of the medial and lateral mammillary nuclei in normal cat brains, and of the same structures (after quasi-equilibrium of the cellular populations is achieved) in brains of these experimental animals modified by unambiguous lesion arrays, provides the foundation for deciphering features of the neuronal circuitry that cannot be elucidated on the basis of qualitative neuroanatomic knowledge. This paper is concerned first with the closeness of agreement of cell population values between bilaterally corresponding mammillary nuclei in the same brain and with the degree of reproducibility of the ratio of the populations of the lateral and medial nuclei of this complex from one brain to another. Second, it is concerned with illustrating in specific cases the usefulness of population ratios determined from normal and from modified brains in revealing important neuroanatomic relations: (1) clarifying the structure of the dorsal bifurcation of the principal mammillary tract into the mammillothalamic and mammillotegmental tracts for fibers projecting from the medial mammillary nucleus, and (2) deciphering the neuronal circuitry of the bilateral projection of each lateral mammillary nucleus to the anterior dorsal nuclei of the thalamus.
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  • 90
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Chick embryos, incubated at 38-39°C to stages 8-11 (Hamburger-Hamilton staging), were injected (under the vitelline membrane) with ten MLD (mice) per 0.05 ml of tetanus toxin or with avian physiological saline solution. Seventeen hours after the injection the embryos were harvested and fixed in Bouin's solution. Selected control and experimental specimens were sectioned for histological study.Observations of gross specimens show that open neural folds of younger embryos are more susceptible than are the more extensively closed tubes of older embryos. The progressively more caudal restriction of toxin-susceptible sites with increasing age is a manifestation of this correlation with the degree of closure at injection time.Study of serial sections establishes the concentration of lesions almost exclusively in neural tissue, especially in the alar region of the neuraxis. Tetanus-induced lesions include encephaloschisis, myeloschisis and platyneury at various levels of the neural tube. These basic defects are comparable to those reported after treatment with many CNS teratogens.Suggestions are made concerning the possible effect of tetanus toxin on biochemical interactions that might lead to aberrations from the normal morphogenesis of the central nervous system.
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  • 91
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The rates of proliferation and developmental capabilities of reticular cells in the hemopoietic tissues of the rat were studied after administering single and multiple injections of tritiated thymidine. Radioautographic analyses were made using both smears and sections of the various hemopoietic tissues. Liquid scintillation counting of tissues was also employed. Sublethal gamma irradiation was administered to animals previously labeled with H3-thymidine in order to evaluate the role of reticular cells during the repopulation of the marrow.The labeling patterns (per cent label and average grain count) of reticular cells, both phagocytic and non-phagocytic types, are compared with the labeling patterns of blast cells. It is shown that reticular cells are proliferating at a slow rate and do not demonstrate the labeling patterns expected of stem cells for the rapidly proliferating myeloblasts, pronormoblasts, lymphoblasts and megakaryoblasts. The labeling patterns of cells which are generally believed to precede the committed blast cells, the hemo-cytoblasts, are also discussed and are contrasted with the labeling patterns of the reticular cells. During recovery from sublethal irradiation there was no evidence of differentiation or transformation of labeled reticular cells into blast cells of the various blood cell lines. The labeling patterns of blast cells suggest that the great majority are derived from members of their own group and that any proposed precursors of these blasts would need to be relatively few in number, rapidly proliferating and highly radiosensitive.
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  • 92
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Gross examination of the chimpanzee skull revealed that: there are three ethmoidal sinuses; the sphenoid sinus is immense and is divided into a superior and inferior part; the huge maxillary sinus contains a distinct bony canal for the nasolacrimal duct; the anterior and middle ethmoidal sinuses drain into the superior meatus; the frontal sinus drains via the middle ethmoid; the posterior ethmoid and sphenoid sinuses open into the sphenoethmoidal recess and also communicate with each other; the maxillary sinus opens into the middle meatus through a large ostium; the nasolacrimal duct drains into the inferior meatus; the mastoid process is small but contains a central cavity which communicates with the middle ear; the broad and smooth planum tympanum serves as the floor of the external auditory canal, the latter forming an angle of 30° with the horizontal; the tympanic membrane makes an angle of 30° with the floor of the canal and is deeply recessed antero-inferiorly; except for the extreme slope of the tympanic membrane and the malleus, the middle ear is similar to man; the inner ear is likewise similar; the carotid artery and the large carotid plexus lie in a definite osseous tube surrounded by pneumatized bone but attached to the periotic capsule; the chimpanzee is subject to otitis media.
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  • 93
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    The @Anatomical Record 155 (1966), S. 111-115 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Mucosal cellular populations and glandular thickness in the corpus of the canine stomach was assessed in 30 dogs. The average number of mucous neck cells per “swath” of full thickness mucosa over a width of 0.223 mm was 41 (S.E. ± 2.09), of parietal cells, 95 (S.E. ± 8.71), of chief cells 205 (S.E. ± 12.63). The average glandular thickness was 557 μ (S.E. ± 24.71).The distribution of cells in the stomachs of four additional dogs was determined. More mucous neck cells were noted in the glands of the juxta-antral and cardiac zones than in those of the corpus. Few parietal and chief cells were noted in the cardiac zone. In the corpus, however, these cells were abundant and evenly distributed.The data presented permit calculation of the total gastric mucosal cellular population of the stomach from an “average” 15 kg dog. The acid-pepsin secreting area has a volume of 35 cm3, and therefore contains 4.3× 108 parietal cells, 7.2 × 108 chief cells, and 1.4 × 108 mucous neck cells.
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  • 94
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Two cases are described in which enormous bloodless peritoneal sacs occupy the abdominal cavity and enclose the small intestines. Back of the sac the colic arteries and veins are in normal anatomical position. The inferior mesenteric vein has been converted into a fibrous cord with resulting reversal of venous return from the hindgut into the hypogastric vein. These cases conform to Papez's concept of the so-called paraduodenal hernia: the peritoneal sac is derived from the embryonic umbilical peritoneal cavity. The authors suggest that most, if not all large intraperitoneal sacs, the so-called paraduodenal hernias, are derived from the embryonic umbilical peritoneal diverticulum.
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  • 95
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Three specimens from Balaenopteran whales have been available for study: a 20 mm embryo, a fetus 57 inches long and the ampulla duodeni of a 47-foot adult. By reconstruction, dissections and histological preparations, it has been possible to show that the extrahepatic portion of the bile duct is really an elongated hepato-pancreatic duct receiving ductules draining both rostral and caudal pancreatic lobes. After coursing through the pancreas, this duct pierces the intestinal muscle at the beginning of the pars descendens duodeni, then runs through the whole length of the longitudinal fold before emptying at the bottom of the pars descendens. In the adult, maceration methods have demonstrated that there is no vestige at all of a sphincter of Oddi. Presumably, this is a consequence of the absence of the gall bladder. Contrary to statements in the literature, a complete foramen epiploicum, vestibule and lesser peritoneal sac could be demonstrated as well as a long infracardiac bursa. Most interesting is the presence of a sizable valve in the portal vein at the point where it enters the liver.
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  • 96
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    The @Anatomical Record 155 (1966), S. 251-260 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The histological structure of the squamo-columnar junction of the cervix uteri of mice was studied during the estrous cycle, pregnancy, lactation, and in ovariectomized and estrogen-stimulated animals. In the absence of endogenous or exogenous estrogen, there was no clear demarcation between the squamous and the columnar epithelium; the epithelium in the zone of transition resembled types previously described in the human cervix that have been regarded as evidence of a metaplasia of columnar to stratified epithelium. However, in the mouse, estrogen stimulation caused the disappearance of the transitional zone so that an abrupt junction resulted. It was concluded that the type of junction is controlled by estrogen, and that the stratified epithelium of the transitional zone may differentiate to produce either keratinized cells or cells of uterine type at its surface.
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  • 97
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    The @Anatomical Record 156 (1966), S. 11-17 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A study was made of the growth of hair in the ventral gland of the adult male gerbil, Meriones unguiculatus. The gland is composed of pilosebaceous complexes in which the hair follicles exhibit a very long anagen and a short telogen. Castration causes an almost immediate cessation of growth of the gland follicles. Daily treatment with 320 μg testosterone proprionate results in re-establishment of hair growth within 72 hours. Growth continues and at three weeks the ventral gland resembles that of normal animals. No influence was observed of the physiological hair cycle of the general skin on the follicles of the ventral gland or of testosterone on the hair cycle of the general skin. The pilosebaceous complexes of the mid-ventral skin of the male gerbil are androgen sensitive and differ both morphologically and physiologically from those of the general skin.
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  • 98
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    The @Anatomical Record 156 (1966), S. 41-53 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Angiocardiography was used to investigate cardiovascular flow patterns in the heart and great vessels of the bullfrog and the marine toad. In the frog, these studies revealed a completely selective distribution of right atrial blood to the pulmocutaneous arches. The selective distribution is affected, in part, by the ventricular trabeculae which maintain in the ventricle a separation of right and left atrial blood, by the sequential movement from the ventricle of first right and then left atrial blood, and by a sphincter-action at the point of division of the truncus arteriosus which effectively shunts right atrial blood into the pulmocutaneous circuit. Left atrial blood in the frog is initially distributed selectively to the systemic arches; late in ventricular systole, some left atrial blood enters the pulmonary circuit. In the toad, both left-to-right and right-to-left mixing appear to occur, but only after significant periods of selective distribution.
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  • 99
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The typical jejunal villus is tongue- or chisel-shaped, in which the lacteal is axial, the artery paraxial and the vein lies near one of the lateral borders. The artery forms a T-junction with the specially wide marginal capillary at the tip which distributes blood to the greater part of the subepithelial capillary plexus. This plexus is so dense that no epithelial cell is more than 30 μ away from the blood stream. The higher density of the plexus in the tip reflects the higher functional capacity of the epithelium there and the plexus in the base of the villus is less dense in keeping with the lower functional capacity of the basal epithelium. The veinbegins in a manner which does not suggest the presence of an arterio-venous anastomosis.
    Type of Medium: Electronic Resource
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  • 100
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Complete and partial transposition of the great vessels, dextrocardia, and absence or stenosis of the tricuspid or mitral valves were encountered singly or in combination in rat fetuses from mothers injected with trypan blue solution subcutaneously on the 8th or 9th day of gestation. Hearts with transposition of the great vessels were usually characterized by shortness of the aorta and pulmonary trunk, cranial location of the aortic valve, displacement of the coronary arteries, and a channel or “track” extending from the cranial portion (infundibulum) of the right ventricle to the commencement of the transposed pulmonary trunk. Inadequate expansion of the atrioventricular ring about the 12th or 13th day of gestation possibly leads to deformity of the atrioventricular cushions and to absence or stenosis of the tricuspid or mitral valves. Sinuosity of the truncus arteriosus seen in many 13th day and older embryos of the trypan blue series is considered a significant factor in the development of transposition of the great vessels.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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