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  • NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS
  • Life and Medical Sciences
  • 1970-1974  (96)
  • 1935-1939  (21)
  • 1930-1934  (11)
Collection
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 79 (1972), S. 293-298 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relative proliferative capacity of haematopoietic cell populations derived from 22-week-old adult bone marrow and 14-18 day foetal liver has been studied in lethally irradiated syngeneic recipients by means of chromosome markers. Although starting at a disadvantage in terms of the number of colony-forming units (stem cells) injected, the foetal liver-derived populations steadily increased their relative numbers in the myeloid and lymphoid tissues over a period of several weeks until a plateau was reached. It is suggested that stem cells in foetal liver have, on average, a higher intrinsic capacity for self-renewal than do those in bone marrow, and that this capacity falls to the adult level within about ten weeks of transfer.
    Additional Material: 1 Ill.
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  • 2
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Lymphopoiesis with respect to recirculating and non-recirculating small lymphocytes was measured simultaneously in rats thymectomized as adults. Removal of the thymus at four to five weeks of age had a profound inhibitory effect upon the production of recirculating cells, whereas the formation of non-recirculating lymphocytes was only slightly depressed. Thymectomy had approximately the same impact of lymphopoiesis as thymectomy and exposure of the animal to a large dose of whole body X- and γ-irradiation. The latter finding, and the failure of a thoracic duct cell transfusion to augment lymphocyte production, accord with the view that the thymus is the principle intermediate source of recirculating small lymphocytes in the normal, unstimulated animal.
    Additional Material: 5 Tab.
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  • 3
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A method is described for measuring lymphopoiesis that enables the production of recirculating and non-recirculating small lymphocytes to be estimated simultaneously. Using this technique, experiments were undertaken to determine whether the production of recirculating cells is influenced by the number present in the recirculating lymphocyte pool. The results suggest that neither a massive lymphocyte transfusion nor depletion of the pool by whole body irradiation or chronic lymph drainage affect the rate at which recirculating small lymphocytes are generated.
    Additional Material: 1 Ill.
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  • 4
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The calcitonin (SCT) from salmon ultimobranchial bodies which (like mammalian calcitonins) lowers the plasma calcium concentration in mammals can also affect cyclic AMP (cyclic adenosine 3′,5′-monophosphate) metabolism and proliferation of lymphoblasts in normal and prostaglandin E1 (PGE1)-treated rat thymocyte populations in three different ways. In the first case, low concentrations (0.5-5.0 ng per milliliter) of SCT lower (by a calcium-mediated process) the ability of PGE1 to transiently increase cyclic AMP synthesis, but the reduced surge of cyclic AMP production is still ample to stimulate lymphoblasts in the cell population to initiate deoxyribonucleic acid (DNA) synthesis. Secondly, these low SCT concentrations affect the eventual progression of the PGE1-stimulated, DNA-synthesizing lymphoblasts into mitosis by a calcium-mediated process. Depending on the extracellular calcium concentration and the magnitude of the initial increment in the intracellular cyclic AMP content, SCT can either promote or inhibit the progression of the stimulated cells into mitosis. SCT's third action is a rapid (within 5 minutes), calcium-independent elevation of the cellular cyclic AMP content in otherwise untreated thymic lymphocyte populations exposed to a very high concentration (100 ng per milliliter) of the hormone. This early, transient rise in the cyclic AMP level is followed by a calcium-dependent increase in lymphoblast proliferation. An attempt is made to interrelate and explain the different actions of SCT on cyclic AMP metabolism and mitogenesis.
    Additional Material: 10 Ill.
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  • 5
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Tab.
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  • 6
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    Unknown
    PANGAEA
    In:  Supplement to: Wiseman, J D H (1937): Basalts from the Carlsberg Ridge, Indian Ocean. In: Geological and Mineralogical Investigations, The John Murray Expedition 1933-1934 - Scientific Reports. British Museum ( Natural History ), London, United Kingdom, 3(1), 2-31, hdl:10013/epic.46160.d006
    Publication Date: 2023-08-28
    Description: During the cruise of the" Mabahiss" from Zanzibar to Colombo at Station 133 (1° 25' 54" S. to 1° 19' 42" S. and 66° 34' 12" E. to 66° 35' 18" E.) several small rock fragments were brought up in the Monegasque net; and, since at this position there is no possibility of the material being transferred by floating Ice, these specimens are of some interest as samples of oceanic rock foundations. All the rocks have a black appearance, but in the majority this skin is of negligible thickness. Exceptionally, however, it may attain to 1/3 in. (St. 133, 8), and then the specimens are rounded. The coating is made of dark opaque manganese material. At Station 166 one or two similar specimens of angular basalt were found in the trawl consisting mainly of manganese nodules.
    Keywords: NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 63 (1938), S. 229-261 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although thoracic diverticula of the aorta ending dorsally in pulsatile organs were discovered by Brocher as early as 1917 no detailed account of their structure was published. The condition of these structures in the adult was not investigated and their development through larval instars was not followed. Brocher's later papers announced the discovery of similar organs in the orders Orthoptera, Coleoptera and Lepidoptera. In 1931 E. Meyer described in some detail pulsatile organs in the Ephemerida. In general these accounts are either superficial or of doubtful interpretation.The present paper deals with the Odonata and stresses the Anisoptera. Anax junius has been studied as the type both anatomically and histologically in all stages of larva and imago except the first four instars. Other types have been compared with Anax, and some of the other orders mentioned have been checked for presence and nature of these organs.Aortic diverticula and pulsatile organs occur in all Odonata both larval and adult. These are derived from the same origins and their histology is that of the membranes involved in aortic and body walls. Through inference from morphology and from physiological examination it appears that pulsatile organs (1) supplement heart action, perhaps substituting for it during emergence. (2) assist in the functioning of the ostia and ostial glands, and (3) may even be important in production and distribution of hormones.
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  • 8
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Data concerning the seasonal distribution of twenty-two species of nudibranchs are recorded for a period of 9 months. The occurrence of copulation and of egg laying for these animals in the laboratory aquaria is recorded for the same period. These data indicate that the seasonal distribution of certain species is well marked, and that there is in many cases a definite breeding season.The characteristics of the egg ribbons of these nudibranchs are described, and figured by means of photographs. These egg ribbons approach the mathematical form of a spiral of Archimedes. In every case observed, the ribbon was deposited in a counter-clockwise direction, viewed dorsally.The relationship between these observations and earlier work on the life histories of the nudibranchs is discussed.
    Additional Material: 5 Tab.
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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: Salivary gland nuclei in Chironomus regularly show large, conspicuous nucleoli. In Sciara no true nucleoli have been found, but sometimes certain particular chromosome regions expand greatly, forming ‘puffs’ or ‘bulbs,’ somewhat nucleolus-like in nature. Detailed study has been made of the chromosome structure in the affected regions in both genera.In the nucleolar regions of Chironomus the banded structure of the chromosome is distinctly modified. In the case of the large nucleolus the chromosome breaks up into a heavy network in which solid discs are replaced by interconnected chromatic spheres and granules, extending out somewhat into the clear nucleolar substance. In the case of the smaller nucleolus, Balbiani's ring, the banded structure is less disturbed. A chromatic network, resembling a system of rootlets, runs out from the chromatic bands into the clear nucleolar substance.In Sciara ocellaris the ‘puff’ regions are at times normally banded, but at other times in the condition described as ‘puffed.’ The same is true of the ‘bulb’ regions. The relation between nucleoli, puffs and bulbs is discussed. Also that between ‘heterochromatin’ and ‘euchromatin.’ Evidence seems to indicate that the latter are merely extremes in a continuous range involving different relative amounts of chromatic and achromatic materials. The ‘puff’ regions appear to be structurally similar to the chromocenter in Drosophila.
    Additional Material: 1 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: The morphology of the retinal pigment epithelium and photoreceptor cells has been studied in the common newt Triturus viridescens dorsalis by light, conventional transmission and scanning electron microscopy.The pigment epithelium is formed by a single layer of low rectangular cells, separated by a multilayered membrane (Bruch's membrane) from the vessels of the choriocapillaris. The scleral border of the pigment epithelium is highly infolded and each epithelial cell contains smooth endoplasmic reticulum, myeloid bodies, mitochondria, lysosomes, phagosomes and an oval nucleus. Inner, pigment laden, epithelial processes surround the photoreceptor outer and inner segments.The three retinal photoreceptor types, rods, single cones and double cones, differ in both external and internal appearance. The newt, rod, outer segments appear denser than the cones in both light and electron micrographs, due to a greater number of rod lamellae per unit distance of outer segment and to the presence of electron dense intralamellar bands. The rod outer segments possess deep incisures in the lamellae while the cone lamellae lack incisures. Both rod and cone outer segments are supported by a peripheral array of dendritic processes containing longitudinal filaments which originate in the inner segment. The inner segment mitochondria, forming the rod ellipsoid, arelong and narrow while those in the cone are spherical to oval in shape. The inner segments of all three receptor cell types also contain a glycogen-filled paraboloid and a myoid region, just outside the nucleus, rich in both rough and smooth endoplasmic reticulum. The elongate, cylindrical nuclei differ in density. The rod nuclei are denser than those of the cones, contain clumped chromatin and usually extend further vitreally. Similarly, the cytoplasm of the rod synaptic terminal is denser than its cone counterpart and contains synaptic vesicles almost twice as large as those of the cones. Photoreceptor synapses in rods and cones are established by both superficial and invaginated contacts with bipolar or horizontal cells.
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