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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of clinical periodontology 18 (1991), S. 0 
    ISSN: 1600-051X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract The development of an assay for markers of active periodontitis, obtained directly from gingival crevicular fluid (GCF) and simply quantified, would be of great importance to the dental practitioner. The purpose of this study was to evaluate direct and indirect immunodot techniques as to their potential in easily quantifying acute-phase proteins within periodontally diseased and healthy site GCF. Indirect immunodots (GCF eluates dotted onto nitrocellulose membrane) using monoclonal antibodies and a radioactive isotope label were used to identify and establish relative amounts of C-reactive protein (CRP) and alpha-2-macroglobulin (A2M) in 2 diseased and 2 healthy sites in 24 periodontitis patients. Periodontally diseased sites were found to contain significantly lower concentrations of A2M than healthy sites (p 〈 0.001), but CRP levels did not vary significantly between healthy and diseased locations. Using a direct immunodot assay (GCF absorbed directly into nitrocellulose membrane strips), A2M levels quantified with radioactive isotopes at healthy and diseased sites could be correlated with A2M levels determined by enzyme-linked antibody-colormetric probes at those same sites. Such a direct sampling and quantification system shows promise for future “in-office” diagnostic methodology.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 23 (1988), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A double labeling technique was developed to detect T cell phenotype and HLA-DR (activation) antigens on infiltrating cells in gingival biopsy sites classified as either periodontally active (≥ mm attachment loss within past 3 months), clinically similar but stable, or healthy. Serial cryostat sections were obtained from each of the above disease category biopsies in 13 periodontal maintenance patients, and were processed with sequential Leu series (T cell subsets) avidinbiotin-peroxidase followed by anti-HLA-DR indirect alkaline phosphatase labeling protocols. Labeled cells were counted in repeatable fields in the sulcular, middle and oral thirds of each section, and HLA-DR+ T cells (activated) were calculated. Total HLA-DR-labeled cells and HLA-DR-positive pan-T cells and T helper cells (Th) were all more numerous in active specimens than in healthy sites (p〈0.05), and in sulcular fields than in the oral third of the section (p〈0.05). Although activated T suppressor cell (T5) densities did not vary statistically according to tissue location, active biopsies had more cells per field than either stable or healthy specimens (p〈0.05), especially in the sulcular third. A majority of pan-T, Ts and Th cells appeared to display activation markers in active, stable and healthy biopsies. This study supports the functional role of T lymphocytes in modulating the immune response in periodontal tissues.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 31 (1996), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Cigarette smoking is a major risk factor in the development and further progression of periodontitis. However, little is known regarding the pathogenesis of smoking-related periodontal diseases. The purpose of this study was to examine the effects of nicotine, alone and in combination with lipopolysaccharide (LPS), on monocyte secretion of bone-resorbing factors, PGE2 and IL-1β. Peripheral blood monocytes (PBM) were isolated by counterflow centrifugal elutriation from 15 healthy, non-smoking donors. PBM were incubated for 24 h in RPMI 1640 containing nicotine (0, 50 μg/ml, I μg/ml, 10 μg/ml and 100 μg/ml) with or without 10 μg/ml Porphyromonas gingivalis LPS or Escherichia coli LPS. Culture supernatants were assayed for PGE2 and IL-1β by ELISA. None of the nicotine preparations resulted in significant PBM secretion of PGE2 and IL-1β above that of unstimulated cultures. However, PGE2 release was potentiated 1.7-fold by the combination of P. gingivalis LPS and 10 μg/ml nicotine relative to P. gingivalis LPS alone (p〈0.05, one-way ANOVA). Prostaglandin E3 release also was potentiated 3.5-fold by P. gingivalis LPS and 100 μg/ml nicotine relative to P. gingivalis LPS alone (p〈0.00001, one-way ANOVA) and 3.1-fold by E. coli LPS and 100 μg/ml nicotine relative to E. coli LPS alone (p〈0.00001, I. one-way ANOVA). IL-1β secretion was lower for either LPS plus 100 μg/ml nicotine relative to LPS alone, although not significantly. These data demonstrate upregulation of LPS-mediated monocyte secretion of PGE2 by nicotine and suggest a potential role for nicotine in periodontal disease pathogenesis.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 29 (1994), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Interleukin-1 beta (IL-1β) may be related to the pathological processes associated with periodontitis, primarily due to its ability to induce collagenase, increase neutrophil chemotaxis, and stimulate bone resorption. This study was designed to histologically quantitate IL-1β positive cells from various histologic fields in untreated gingivitis/early periodontitis (G/EP) versus moderate /severe periodontitis (M/SP) gingival tissues, and associate these with collagen loss. Two gingival biopsies from 8 patients were collected, one from a G/EP site and one from a M/SP site. Mouse monoclonal antibodies in combination with an avidin-biotin-peroxidase system were used to stain for IL-1β, while the van Gieson method was used to stain for collagen in serial sections. Collagen loss in G/EP (35%) and M/SP (52%) fields was consistent with gingivitis and periodontitis, respectively. IL-1β positive cells in combined coronal/sulcular (Co/Su) and apical/sulcular (Ap/Su) fields (nearest the bacterial insult) were significantly more numerous compared to combined coronal/middle (Co/Mi) and apical/middle (Ap/Mi) fields (p 〈 0.05). While numbers and percentages of IL-1β positive cells were generally higher in M/SP biopsies, differences were not significant. Further, there was no correlation between the number of IL-1β positive cells and percent collagen loss. However, a significant correlation between IL-1β positive cells and corresponding gingival crevicular fluid IL-1β concentrations was noted (r = 0.65, p = 0.01). Through the use of immunohisto-chemistry, this study demonstrated that the presence of IL-lβ+ cells does not appear to have a direct association with collagen loss.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 28 (1993), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Recent studies of the cellular mechanisms involved in chronic inflammatory periodontal disease (CIPD) have contributed significantly to our understanding of the pathogenesis of the disease process. Functional studies have demonstrated polymorphonuclear neutrophil (PMN) chemotactic defects in some 70% of subjects with localized juvenile periodontitis while chemiluminescence data have suggested that periphertal blood PMNs from young subjects with adult periodontitis (AP) may be in a metabolically active state. Further studies have shown that stimulation of PMNs with a number of periodontopathic bacteria resulted in the production of an IL-1 inhibitor suggesting a possible regulatory role for PMNs in CIPD in addition to their established protective role. Most work on the immunoregulation of CIPD has, however, concentrated on T-cells. Recent limit dilution analysis has demonstrated the presence of periodontopathic bacteria-specific T cells in peripheral blood and the involvement and homing of these cells to the local lesions of CIPD is currently the focus of many studies. In animal studies, Actinobacillus actinomycetemcomitans (Aa)-specific T-cell clones home to the gingival tissues where they may exert a protective role. Homing and retention of lymphocytes to and in specific sites is dependent upon the expression of adhesion molecules. Recent data indicate however, that while there are increasing levels of ICAM-1, LECAM-1 and PECAM-1 expression with increasing degrees of inflammation, there are no differences between gingivitis and periodontitis lesions. Cytokine profiles may be related to the role of T-cell clones homing to the gingiva in CIPD. In subjects susceptible to periodontal breakdown there may be an increase in the type 2 IL-4 producing T-cells whereas in non-susceptible subjects, type 1 IL-2/IFN-γ producing T-cells may preferentially home to the gingiva. This hypothesis is generally supported by recent data obtained from human studies but data obtained from animal studies is only partly supportive and may suggest the opposite. Nevertheless, it is now possible to construct a testable framework or model of CIPD based on these cellular and molecular mechanisms.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 29 (1994), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Inflammatory mediators released as a result of smokeless tobacco (ST)-induced irritation may play a role in the development of oral mucosal lesions at habitual tobacco placement sites in ST users. The present study examined levels of interleukin-1 (IL-1) and prostaglandin E2 (PGE2) in ST-induced mucosal lesions and compared these to mediator levels in clinically normal mucosa. Soft tissue biopsies were obtained from white mucosal lesions at habitual placement sites and normal alveolar mucosal tissue at non-placement sites in 18 ST users. Fifteen non-tobacco using subjects also provided normal alveolar mucosal biopsies. IL-1 and PGE2 were recovered from the specimens, and mediator levels were determined by enzyme immunoassay. Prostaglandin E2 levels (pg/mg) were lower in both regions in the ST subjects, but values did not vary significantly between the regions with 2.77±0.72 and 2.86±0.99 at placement and non-placement sites, respectively, in ST users and 7.31±3.84 in non-tobacco users. Both IL-1α and IL-lβ (pg/mg) were significantly (p 〈 0.0I) elevated in ST lesions (IL-lã=25.56±4.00; IL-1β=7.76±1.68) compared to either non-placement sites in ST users (IL-lα=14.64±2.65; IL-lβ=1.63±0.72) or non-tobacco users (IL-lα=12.84±2.60; IL-lβ=2.04±0.75). In view of IL-l's role in keratinocyte proliferation and its inflammatory effects, this cytokine may contribute to mucosal and gingival alterations observed in ST users.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-1424
    Schlagwort(e): intestine ; epithelial transport ; chloride channels ; selectivity ; inactivation ; bilayer reconstitution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Summary Vesicles derived from epithelial cells of the colonic mucosa of the rat were fused to planar phospholipid bilayer membranes, revealing spontaneously switching anion-conducting channels of 50 pS conductance (at-30 mV with 200mm Cl− each side). The equilibrium selectivity series was I− (1.7)/Br− (1.3)/Cl− (1.0)/F− (0.4)/HCO 3 − (0.4)/Na (〈0.11.). Only one dominant open-state conductance could be resolved, which responded linearly to Cl− concentrations up to 600mm. The singlechannel current-voltage curve was weakly rectifying with symmetrical solutions. When 50 mV were exceeded at the highconductance branch of the curve, switching was arrested in the closed state. At more moderate voltages (±40 mV) kinetics were dominated by one open state of about 35-msec lifetime and two closed states of about 2 and 9-msec lifetime. Of these, the more stable closed state occurred less often. At these voltages one additional closed state of significantly longer lifetime (〉0.5 sec) was observed.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1546-1718
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] X–linked hypophosphatemic rickets (HYP) is a dominant disorder characterised by impaired phosphate uptake in the kidney, which is likely to be caused by abnormal regulation of sodium phosphate cotransport in the proximal tubules. By positional cloning, we have isolated a candidate gene from ...
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Plasma chemistry and plasma processing 5 (1985), S. 293-316 
    ISSN: 1572-8986
    Schlagwort(e): Plasma chemistry ; halocarbon decomposition ; kinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Technik allgemein
    Notizen: Abstract For the case of weak feed gas decomposition, where the concentration of CCl4 exceeds those of decomposition and built-up products, the emission of CCl* is shown to originate from dissociative excitation of CCl4. With electron concentration measured independently, the kinetics of CCl4 decomposition has been extracted from the time dependence of the CCl* intensity. Supported by EPR determinations of radical concentrations in rapidly flowing CCl4 and CCl4/O2 afterglows, the primary decomposition reaction is shown to be the electron impact dissociation into CCl3 and Cl. Its rate constant (k 1=4×10−8 cm3s−1) indicates strongly that dissociative electron attachment is the main reaction channel at least at r.f. power densities just above the threshold of a self-maintaining discharge. At extremely low mean electron energies the emission of a continuum is observed, which is tentatively ascribed to the radiative CCl3-Cl recombination.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1434-601X
    Schlagwort(e): 21.10.Re ; 23.20.Lv ; 27.60.+j
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The70Ge(α,nγ)73Se reaction was used to populate medium spin states of the73Se nucleus. Spins and parities up to about Iπ=(21/2+)ħ were determined by gamma angular distribution, gamma linear polarization and excitation function measurements.
    Materialart: Digitale Medien
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