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  • 1
    ISSN: 1420-9071
    Keywords: Key words. Phagocytosis; cyclosporine A particles; morphometry; latex particles.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The aim of this study was to develop an in vitro model to estimate the clearance of pulmonary administered cyclosporine A (CsA). To do this we estimated the volume of CsA particles phagocytosed by alveolar macrophages (AM) lavaged from hamsters. AM were cultured with CsA particles at two doses of particles (0.1 mg or 0.5 mg) and at three incubation times (1 h, 6 h or 24 h). The AM were also incubated with or without latex particles. After incubation, AM were processed for light and electron microscopy and the mean volume of phagocytosed particles was esti mated stereologically from micrographs of the cells. Here, however, the CsA particles were dissolved during the embedding process and only their negative images (vacuoles) could be detected. An indirect method was therefore developed. The volume of cytoplasmic vacuoles (called 'background' vacuoles) was estimated in control macrophages (without particles or with latex particles and subtracted from the total volume of vac uoles in macrophages incubated with CsA, which gave the volume of phagocytosed CsA. The volume of the 'background' vacuoles remained constant in all study conditions. At a dose of 0.1 mg CsA the volume phagocytosed per macrophage was 13.83 μm3 at 1 h, 8.43 μm3 at 6 h and 4.50 μm3 at 24 h. At a dose of 0.5 mg CsA, the volume phagocytosed varied from 26.59 μm3 at 1 h, to 4.13 μm3 at 6 h and 49.10 μm3 at 24 h. These results show no statistically significant dependence on time for either dose, and a statistically significant dose effect only at 24 h. With latex particles, the phagocytosed volume increased significantly with time and dose and was significantly higher than for CsA particles. This study showed that CsA particles are phagocytosed by AM from hamsters but to a lesser extent than latex particles. This difference could be correlated with physical properties, i.e. a difference between particle size and shape and/or chemical properties, latex particles being inert and CsA particles being peptidic. Moreover, different surface receptors on AM could be involved in the process of phagocytosis of CsA and latex particles.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 617-623 
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Particelle ferromagnetiche immesse per via intratracheale nei polmoni sono fagocitate da macrofagi alveolari. Dopo che queste particelle sono state magnetizzate dal campo esterno, esse producono un campo residuo che decade rapidamente a causa del disallineamento delle particelle dovuto al movimento citoplasmatico (rilassamento). I cambiamenti nel valore di rilassamento nel tempo successivo all’immissione potrebbero essere connessi alla mobilità citoplasmatica.
    Notes: Summary Ferrimagnetic particles instilled intratracheally into the lungs are phagocytized by alveolar macrophages. After these particles are magnetized by an external field, they produce a remanent field which decays rapidly due to particle misalignment from cytoplasmic motion (relaxation). Changes in relaxation rate with time following instillation might be related to cytoplasmic motility.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Structural Biology 105 (1990), S. 146-153 
    ISSN: 1047-8477
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Journal of Structural Biology 113 (1994), S. 107-116 
    ISSN: 1047-8477
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 15 (1988), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract The aim of the present study was to investigate stereologically the histologic alterations occurring during gingival healing after experimental gingivitis and to compare clinical parameters with histological findings. 8 dental students volunteered for the investigation. After a prophylaxis, they performed optimal oral hygiene to reach mean plaque and gingival indices approaching zero. They then abolished all oral hygiene procedures for a period of 21 days. After this experimental gingivitis phase, they again performed optimal oral hygiene for 8 days to restore gingival health. At days 0. 1, 2, 4, and 8 after experimental gingivitis, the plaque index (PII), the gingival index (GI) and the gingival exudate flow rate (GEFR) were assessed and their buccal gingiva was biopsied. Point counting procedures were performed at 2 different levels of magnification on light microscopic sections to estimate the volume fractions of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The relative numbers of fibroblasts, polymorphonuclear neutrophils. lymphocytes, plasma cells and macrophages were estimated by counting the number of profiles of these cells in a specific connective tissue area adjacent to the apical end of the junctional epithelium. A rapid drop in the PII was noted with increasing time after oral hygiene, followed by a slower decrease in the GI and GEFR scores. The histological picture during the entire experiment was that of an initial gingival lesion. At day 0, no chronic inflammation of the gingiva characterized by a predominance of plasma cells was observed. After resumption of oral hygiene when the relative cell numbers at day 0 and day 8 were compared, only an increase in the PMN population was observed. As GI and GEFR scores decreased no significant changes were noted in the relative numbers of the various cell types. These observations suggest that the “physiogenesis during experimental health” appears first clinically and then histologically, and hence, it may take more than 8 days to observe significant variations in cell populations.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 16 (1989), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract The aim of the present study was to compare stereologically the histo-pathologic variations following 3 weeks of chemical (chlorhexidine) or mechanical plaque control. 18 students and denial hygienists volunteered for this investigation. After prophylaxis, they performed optimal oral hygiene to reach mean plaque and gingival indices approaching. 0.Six of them then performed mechanical plaque control of 3 weeks (control), while the other 12 rinsed 3 times daily with a 0.12% chloridixidine solution (test). At days 0 and 21. the plaque index (PH), the gingival index (Gl) and the gingival exudate flow rate (GEFR) were assessed and biopsies were obtained from buccal sites. Point-counting procedures were performed at 2 different levels of magnification on light microscopic sections to estimate the volume fractions of epithelium, infiltrated and non-infiltrated connective tissue, and collagen. The relative numbers of fibroblasts, polymorphonuclear neutrophils, lymphocytes, plasma cells, macrophages and mast cells were estimated by counting the number of nuclear profiles of these cells in a specific connective tissue area adjacent to the apical termination of the junctional epithelium. After 21 days, the PIIs of the test subjects were significantly higher than the PIIs of the controls, but their GI were similar. At the end of the experimental period, the various volume fractions and %s of cell profiles remained stable with the exception of an increase in the %s of lymphocytes in the test group. This study has shown that, clinically as well as histologically, the daily use of chlorhexidine for a 3-week period is equally effecient as optimal mechanical tooth cleaning in maintaining a healthy gingiva in the buccal sites investigated.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 15 (1988), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract. The purpose of the present investigation was to study stereologically the histopathologic changes in the gingiva during 6 months of abolished oral hygiene and to study the development of chronic gingivitis in man. After a thorough prophylaxis procedure, 5 dental students performed optimal oral hygiene under supervision for a period of 3 weeks. At the end of this pre-experimental phase, they were asked to abolish all oral hygiene procedures for 4 (2 individuals) to 6 months (3 individuals). At day 21, and after 2, 3, 4, 5 and 6 months, the gingival exudate flow rate and the gingival index were assessed, and buccal gingival biopsies taken. Semi-thin histologic sections were stained with basic fuch-sine and methylene blue. By point counting at 2 different levels of magnification, the volume densities of epithelium, infiltrated (ICT) and non-infiltrated connective tissue, and collagen were estimated. The %s of fibroblasts, PMN's lymphocytes, plasma cells and macrophages were estimated in a predetermined standardized area close to the apical termination of the junctional epithelium. With increasing time, the volume densities of the ICT rose concomitantly with a decrease in the volume densities of the collagen. In spite of great interindividual variations, a slow shift in the proportions of some cell populations was consistently observed. While the fraction of PMN's, lymphocytes and macrophages remained stable, a decrease of fibro-blasts (57 to 39%) and an increase of plasma cells (0.2 to 10%) was observed. This study has, therefore, demonstrated that, in 6 months of plaque accumulation, a chronic gingivitis with a predominance of PMN's and lymphocytes develops. During this period of time, the plasma cell fraction increased continuously. However, more than 6 months of neglected oral hygiene appear to be a pre-requisite for the development of chronic gingivitis lesions characterized by a predominance of plasma cells.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Respiration Physiology 40 (1980), S. 33-47 
    ISSN: 0034-5687
    Keywords: Allometric ; Alveolar wall ; Lung diffusing capacity ; Lung morphometry ; Oxygen consumption ; Smallest mammal
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Respiration Physiology 80 (1990), S. 17-32 
    ISSN: 0034-5687
    Keywords: Airway ; Alveoli ; Osmiophilic layer ; Particle immersion ; Subphase ; Surface tension
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Respiration Physiology 41 (1980), S. 199-210 
    ISSN: 0034-5687
    Keywords: Alveoli ; Pulmonary circulation Lung parenchyma ; Pulmonary diffusion of oxygen Lung volumes ; Pulmonary morphometry
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
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