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  • 1980-1984  (127)
  • 1915-1919
  • 1905-1909
  • 1981  (127)
  • Life and Medical Sciences  (127)
  • 1
    Electronic Resource
    Electronic Resource
    An automated procedure to measure DNA synthesis in preimplantation mouse embryos (1981)
    New York, NY : Wiley-Blackwell
    Gamete Research 4 (1981), S. 121-131 
    Details
    ISSN: 0148-7280
    Keywords: preimplantation mouse embryos ; DNA synthesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This paper describes a sensitive, reproducible, and automated procedure to measure DNA synthesis in preimplantation mouse embryos. Conditions for the DNA synthesis assay have been optimized as follows: (1) 4 μCi/ml3H-thymidine (sp. act. 20 Ci/immole); (2) a labeling period from 2 to 7 hours; (3) a 3-hour preincubation period for blastocysts and from 0 to 7 hours preincubation for 8-cell embryos; and (4) from 1 to 64 embryos per assay. The amount of DNA synthesis per embryo was found to be directly proportional to the number of cells (nuclei) per embryo. The described assay should be useful for future studies on the effect of synthetic and natural compounds on the development of preimplantation mouse embryos, as measured by perturbations in embryonic DNA synthetic activity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120040206
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  • 2
    Electronic Resource
    Electronic Resource
    Biological effects of long-term exposure of rats to 970-MHz radiofrequency radiation (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 2 (1981), S. 279-284 
    Details
    ISSN: 0197-8462
    Keywords: 970 MHz ; rats ; long-term exposure ; serum chemistry ; hematology ; lymphocytes ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rats (N = 16) exposed individually in circularly polarized waveguides to 970-MHz electromagnetic radiation (SAR=2.5 mW/g, 22 h daily for 70 consecutive days) had significantly higher serum levels of triglycerides, albumin, and total protein compared with sham-irradiated controls. No difference was observed in the weights, hematologic profile, or in vitro lymphocyte responses to mitogens between these two groups. The higher serum levels of triglycerides in radiofrequency-radiation-exposed rats suggest a non-specific stress reaction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250020309
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  • 3
    Electronic Resource
    Electronic Resource
    Comparative analysis of the development of the lizard, Liolaemus tenuis tenuis. II. A series of normal postlaying stages in embryonic development (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 169 (1981), S. 337-349 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this work, we have completed a study of the development of the ovoviviparous lizard Liolaemus tenuis tenuis. Ovoviviparity in this lizard is a condition in which eggs are retained within the reproductive duct for about 60 days. During this period the phases of segmentation, gastrulation, neurulation, presomitic, and somitic embryos transpire. During the months of December and January the eggs are laid, and at this time the embryos are comparable to stage 27 Liolaemus gravenhorsti lizard embryos, or to stage 29 Calotes versicolor lizard embryos. Differentiation of the facial region occurs between Days 12 and 42 after egg laying. Limbs develop rapidly between the 8th and 23rd days. By 53 days the appendicular skeleton is completely formed. After 36 days the mesonephros begins to degenerate, and its function is gradually taken over by the developing metanephros. Newborn lizards do not possess an egg caruncle. During the period up to hatching, there is a great increase of liquid within the egg, presumably amniotic fluid. Cracks develop in the leathery shell shortly before hatching and are, perhaps, the first sign of the onset of hatching. Increase of liquid in the egg during postlaying development accounts for its increase in weight and change in shape. Weight of the embryo at hatching does not exceed 32% of the total weight of the egg.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051690307
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of immunization with Freund's complete adjuvant and isologous spermatozoa on the seminiferous epithelium and blood-testis barrier in guinea pigs (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 199 (1981), S. 197-211 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In order to gain insight into the earliest pathological changes underlying the development of autoimmune aspermatogenic orchitis (AIAO) the blood-testis barrier was studied by light and electron microscopy, freeze-etching, and cytochemical techniques early (from 1 to 8 days after adjuvant treatment or isoimmunization). At later times (16 to 21 days) the study was carried out by light microscopy only. Adult male guinea pigs were used either as controls or immunized with Freund's complete adjuvant alone or together with pertussis vaccine. An additional group comprised animals immunized with a suspension of isologous spermatozoa emulsified in Freund's complete adjuvant and with pertussis vaccine. Ultrastructural studies of the testes of experimental animals showed, at earlier periods, apparently normal Sertoli junctions. However, in the adluminal compartment, distended gaps were seen between the facing membranes of adjacent Sertoli cells. At later periods, a massive destruction of the germinal cells were observed. In freeze-fracture replicas, the Sertoli junctions of testes belonging to all the experimental groups were characterized by an irregular network of occasionally interrupted strands of particles associated with the P face (PF). Large concavities determined distensions between interconnecting ridges. The gap junctions were increased in number and in surface. Tracer studies using horseradish peroxidase showed that the marker permeated the myoid cells of a greater proportion of tubules than in control animals. Within the seminiferous epithelium there was only a limited passage of the marker towards the lumina of the tubules. Yet the tracer was always excluded from the adluminal compartment by the Sertoli tight junctions.Our observations suggest the possibility that the FCA causes a loosening of the Sertoli junctions. This condition could enhance exchanges between two antigenically different cellular compartments and, thus, favor occurrence of an autoimmune reaction when cytotoxic factors are experimentally induced, as in iso- or autoimmunization.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091990205
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  • 5
    Electronic Resource
    Electronic Resource
    The mammary gland of the weddell seal, Leptonychotes weddelli (Pinnipedia). I. Gross and microscopic anatomy (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 199 (1981), S. 519-529 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The Weddell seal cow possesses two subcutaneous, ellipsoidal, abdominal mammary glands with a volume of two to three liters when lactating. Corrosion casts reveal that approximately ten large ducts radiate from a gland cistern at the base of the nipple, and end in a complex system of terminal branches. Each gland has a separate arterial supply, mostly from the caudal deep epigastric with a minor contribution from the deep circumflex iliac. Histologically, lactating, nonlactating (resting), and immature glands resemble those of other eutherians. Sinusoidal blood vessels, not observed in the mammary glands of other mammals, are present within lactating but not in resting lobules in the seal. The terminal pouch and lactiferous sinuses possess circular smooth muscle and elastic fibers in the walls, and accumulations of lymphocytes immediately beneath the epithelium. Sebaceous and sweat glands open into the walls of the nipple and the apex of the terminal pouch. There are extensive networks of blood vessels and longitudinal smooth muscle and elastic fibers in the walls and base of the nipple. The possible functions of these morphological observations are discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091990408
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  • 6
    Electronic Resource
    Electronic Resource
    A proposed mechanism for the early development of the human tracheobronchial tree (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 201 (1981), S. 635-640 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The development of the lung in 25 human embryos and early fetuses up to 140 mm crown-rump length was studied by examination of serial histologic sections, morphometry, and selected reconstructions. The proportion of pulmonary tissue consisting of tracheobronchial tree increases during this period. Bronchial cross-sectional diameter, length of the most distal bronchial branches, and thickness of the distal mesenchyme decline during development. The results are consistent with the concept that the dichotomous branching of the growing tracheobronchial tree occurs because of resistance to forward growth of the bronchial branch by compressed mesenchyme, pleura, or adjacent structures. Division and further growth of the bronchus takes place in areas of lower resistance. This process produces a “filling in” of space available for lung development and brings the epithelial and mesenchymal elements into their definitive relationships.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092010407
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  • 7
    Electronic Resource
    Electronic Resource
    The kidney of Leptonychotes weddelli (Pinnipedia: Phocidae) with some observations on the kidneys of two other southern phocid seals (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 167 (1981), S. 13-34 
    Details
    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 kidney of Leptonychotes weddelli was examined using corrosion casts, India ink injection, and histological methods. Some observations were made on the kidney of the crabeater seal (Lobodon carcinophagus) and the elephant seal (Mirounga leonina). The kidneys in all three species are reniculate, as in many other marine mammalian species. Features that have not been described previously in a phocid seal are a peripyramidal muscle, and venous drainage characterized by a large extrinsic system and a small intrinsic system.Examination of specialized fornices, relative medullary thickness, and the volumes of juxtamedullary relative to peripheral glomeruli (all of which relate to urine concentrating ability) revealed that each reniculus of Leptonychotes is similar to the unilobar kidney of a small mammal that produces only moderately concentrated urine. The high glomerular volume to cortical volume ratio may be related to high glomerular filtration rates after feeding observed in marine mammals.It is concluded that reniculation is more likely to be related to the large size of most marine mammals than to some factor related directly to the marine environment.
    Additional Material: 24 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051670103
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  • 8
    Electronic Resource
    Electronic Resource
    Regulation of granulopoiesis and distribution of granulocytes in early phase of bacterial infection (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 109 (1981), S. 17-24 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Studies have been carried out to determine the effect of bacterial infection on CSF production, CFU-C activation, and bacterial clearance by mature granulocytes in mice infected with Escherichia coli. These studies have shown that immediately after bacterial infection (5 minutes), serum colony-stimulating factor (CSF) levels and bone marrow colony-forming units in culture (CFU-C) levels are elevated. This is followed by oscillator rises in both of these parameters and the appearance of granulocytes in the infected site. With clearance of bacteria, CSF and CFU-C levels return to normal. These studies have indicated further that bacterial infection is a major stimulus for granulocyte production through the CSF-CFU-C system and that clearance of bacteria by mature granulocytes may serve as a negative feedback regulatory arm.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041090103
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  • 9
    Electronic Resource
    Electronic Resource
    Proliferative characteristics of clonal endothelial cell strains (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 107 (1981), S. 123-137 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have utilized clonal strains of bovine fetal aortic endothelial cells to study cellular senescence in a differentiated cell type of physiological significance. Serial subcultivation of nine endothelial clones derived from three fetal calf aortas revealed proliferative life-spans in vitro of 53-125 population doublings (PDs), compared with 60 and 143 PDs for two lines of bovine fetal lung cells and 85 and 147 PDs for two lines of bovine vascular smooth muscle cells. Serial growth curves showed marked reductions associated with endothelial cellular senescence both in cellular growth rate and culture plateau density. Studies of the 24-hour [3H]-thymidine labeling index versus percentage of proliferative life-span completed indicated that clonal endothelial cultures contained a large proportion (greater than 90%) of rapidly cycling cells until about 75% of the life-spans were completed. Senescent endothelial cells showed evidence of large increases in cell area, cell volume, and protein content. In those clones examined, one specialized endothelial function, Factor VIII antigen expression, was retained qualitatively throughout the life-spans.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041070114
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  • 10
    Electronic Resource
    Electronic Resource
    Human dermal microvascular endothelial cells in vitro: Effect of cyclic AMP on cellular morphology and proliferation rate (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 106 (1981), S. 253-258 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Macrovascular endothelial cells isolated from the human umbilical vein and microvessel endothelium from the newborn foreskin dermis differ in their requirements for optimal growth in vitor. In the presence of 5 x 10-4 M dibutyryl cyclic AMP (Bt2cAMP), human dermal microvessel endothelial cell proliferation rate increased to give a cell number of 203% of control values by day 10 in culture. The cells retained their characteristic endothelial cell morphology, reached confluence, and could be serially passaged. Cells grown in the absence of Bt2cAMP did not proliferate readily and grew in a disorganized pattern. The effect of Bt2cAMP on microvascular endothelial cell proliferation rate and morphology could be duplicated by cholera toxin (CT) used together with isobutyl methyl-xanthine (IMX). These agents were found to elevate intracellular levels of cyclic AMP in microvascular endothelium over 40-fold. Human umbilical vein cells in culture failed to respond to either Bt2cAMP or CT together with IMX.The growth-promoting effect of dibutyryl cyclic AMP (Bt2cAMP) on human foreskin dermal microvascular endothelium in vitro is in marked contrast to the lack of response of human umbilical vein cells. These results provide further evidence of differences in the mechanisms that regulate macro and microvessel endothelial cell proliferation in vitro.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041060211
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