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Induction and 3D reconstruction of caries-like lesions in an experimental dental plaque biofilm model (2001)

Arnold, W. H. ; Gaengler, P. ; Sabov, K. ; [et al.]

Oxford UK : Blackwell Science Ltd

Journal of oral rehabilitation 28 (2001), S. 0

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ISSN: 1365-2842

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Medicine

Notes: The aim of this study was to examine an in vitro dental plaque model for volumetric assessment and 3D reconstruction of experimentally bacterial induced caries-like lesions. Twenty-three extracted, impacted human molars were coated with a varnish leaving a 3 × 3 mm window on the smooth surface. The teeth were coated with human saliva and Streptococcus sobrinus 6715 adhered onto the enamel via a succrose dependent mechanism. The coated teeth were incubated for 1, 7, 14 and 28 days. At the end of each incubation period microhardness was measured on three sectioned teeth of each incubation period at the enamel surface and at 450 and 750 μm depth perpendicular to the enamel surface. The enamel surface was investigated by scanning electron microscopy (SEM) prior to embedding and serial sectioning of 12 other teeth. The serial sections were studied with polarization light microscopy to investigate subsurface demineralization. The outlines of the caries-like lesions were then traced consecutively on transparencies, digitized and three-dimensionally reconstructed to demonstrate the expansion of the lesion into enamel for volumetric assessment. Microhardness was significantly reduced on the enamel surface after 7, 14 and 28 days incubation. The SEM investigation showed a surface demineralization with dissolution of the prism cores after 28 days incubation. Polarization light microscopy demonstrated caries-like lesions with an irregular expansion into enamel. The results demonstrate that the described method produces caries-like lesions which can be used for further experimental studies regarding demineralization and remineralization processes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1365-2842.2001.00755.x

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Arteriosklerose der Karotisregion (1998)

Dasbach, G. ; Schmitz, I. ; Niehoff, L. ; [et al.]

Springer

Gefässchirurgie 3 (1998), S. 151-157

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ISSN: 1434-3932

Keywords: Schlüsselwörter Karotisdesobliterate ; Arteriosklerose der Karotisregion ; REM-Untersuchung von Karotisläsionen ; Key words Desobliteration of carotid artery ; Arteriosclerotic lesions of carotid artery ; Scanning electronmicroscopy of carotid arteriosclerotic lesions

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Description / Table of Contents: Abstract Atherosclerotic lesions of the carotid artery are a frequent cause of cerebral circulatory disturbance. There is no uniform or even specific morphological substrate for these disease. In order to demonstrate the phase-like development of vascular lesions and the variable findings, 15 surgical samples of the carotid region gained by intramural desobliteration, and 3 vascular cylinders from autopsy material of the carotid artery after previous endarteriectomy were investigated. The analyses concentrated on the demonstration of atherosclerotic alterations at the scanning electron microscopical level as compared to radiological and histomorphological examination. Scanning electron microscopy allows the three-dimensional demonstration of arteriosclerotic lesions. The following major results were demonstrated: • irregular endothelial regions with early stages of thrombus attachment in marginal areas of atheromatous foci; • narrow membrane plates of collagenous fibrous connective tissue with increased texture disturbances and destruction of the lamina elastica interna over soft plaques; • regular step formations on the outer side of the desobliterates over areas of calcifications; and • differentiated repair and healing mechanisms in the vascular bed after surgery.

Notes: Zusammenfassung Häufige Ursachen zerebraler Durchblutungsstörungen sind arteriosklerotische Läsionen der Karotisregion. Den klinischen Befunden liegt dabei kein einheitliches oder gar spezifisches morphologisches Substrat zugrunde. Um den phasenhaften Ablauf der Gefäßläsionen und die variablen Befunde zu dokumentieren, untersuchten wir 15 Operationspräparate der Karotisregion, die durch intramurale Desobliteration gewonnen wurden und 3 aus dem Obduktionsgut stammende Gefäßzylinder der A. carotis nach vorangegangener Endarteriektomie. Der Schwerpunkt der Untersuchungen lag in der Darstellung der arteriosklerotischen Veränderungen im Rasterelektronenmikroskop (REM) im Vergleich mit röntgenologischen und histomorphologischen Untersuchungen. Die REM-Untersuchungen ermöglichten eine räumliche Darstellung der arteriosklerotischen Läsionen. Als wesentliche Befunde ließen sich: • im Randbereich atheromatöser Herde unregelmäßige endotheliale Zonen mit früh beginnender Anhaftung von Thromben nachweisen, •über weichen Plaques schmale Deckplatten von kollagenem Faserbindegewebe mit stärkergradigen Texturstörungen und Destruktionen der Lamina elastica interna belegen, • an der Außenfläche der Desobliterate über Kalzifikationszonen regelhaft Stufenbildungen darstellen, • in dem postoperativ verbliebenen Gefäßbett differenzierte Reparations- und Heilungsmechanismen nachweisen.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/PL00010515

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Induction of Manganese Superoxide Dismutase Gene Expression in Bronchoepithelial Cells after Rockwool Exposure (1998)

Marks-Konczalik, J. ; Gillissen, A. ; Jaworska, M. ; [et al.]

Springer

Lung 176 (1998), S. 165-180

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ISSN: 1432-1750

Keywords: Key words: Gene expression—Crocidolite—Rockwool—Silica—Quartz—Human bronchoepithelial cells—Manganese superoxide dismutase.

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract. Superoxide dismutases play an important protective role in the lung defense against the pro-oxidative effect of fibrous dusts (e.g. crocidolite fibers). Particularly crocidolite, but also other asbestos fibers, are known to induce cellular antioxidant defense. Although rockwool, a man-made fiber made from rock, is used widely for insulation purposes, its effects on the superoxide dismutases in bronchoepithelial cells have not been investigated. Thus, the purpose of this study was to determine whether human bronchoepithelial cells (BEAS 2B) respond to rockwool fibers (115-4 experimental rockwool fiber) by induction of MnSOD mRNA and an increase of MnSOD activity levels. The results were compared with BEAS 2B cells exposed to silica (α-quartz: DQ12; SiO2) and UICC (Union Internationale Contre le Cancer) crocidolite (concentrations of all dusts: 0, 2, 5, 10, 25, 50 μg/cm2= 0, 2.4, 6, 12, 30, 60 μg/ml; 24-h exposure) as control fibers. Scanning electron microscopy confirmed close dust cell contact under all experimental settings. Very low MnSOD mRNA baseline levels rose significantly (p 〈 0.001) in BEAS 2B cells exposed to all three dusts at 2 μg/cm2. However, at 〉25 μg/cm2 MnSOD mRNA levels in silica- and crocidolite- but not in rockwool-exposed cells decreased. Slight (no significance) increases of MnSOD activity were observed which decreased at higher dust (〉5 μg/cm2) concentrations. These results suggest that: (1) like crocidolite and silica, rockwool accelerates MnSOD gene expression in bronchoepithelial cells; (2) an increase of MnSOD mRNA levels is not accompanied by MnSOD activity elevation; (3) in contrast to rockwool, high concentrations (≥25 μg/cm2) of crocidolite and silica reduced MnSOD activity and MnSOD mRNA levels. Because oxidants (H2O2) and crocidolite fibers were shown to reduce SOD activity, lack of active MnSOD protein may be caused by inactivation on a post-translational level. Furthermore, the decline of MnSOD mRNA and MnSOD activity levels coincides with increasing cytotoxicity. In conclusion, rockwool was demonstrated to induce MnSOD gene expression, perhaps because of its pro-oxidative effect in bronchoepithelial cells. In contrast to crocidolite and silica, rockwool fibers are not cytotoxic in this experimental setting.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/PL00007600

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Investigation of corrosion processes on cleavage edges of potash-lime-silica glasses by atomic force microscopy (1995)

Schmitz, I. ; Prohaska, T. ; Friedbacher, G. ; [et al.]

Springer

Fresenius' Zeitschrift für analytische Chemie 353 (1995), S. 666-669

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ISSN: 1618-2650

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract Corrosion phenomena on surfaces of potash-lime-silica glass with medieval composition have been imaged in-situ using AFM in combination with a home built sample holder and a commercial liquid cell. Measurements under ambient atmosphere lead to pit corrosion. Sample preparation and measurement performed under liquids such as isobutanol inhibit the corrosion process. Addition of water (10 vol%) induces the formation of a leached layer, where the network modifiers such as K and Ca are exchanged by hydrogen-bearing species. During the measurements interactions of the tip with the sample surface have been observed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00321346

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