Application of stereologic methods to stratified gingival epithelia

Stereologic point-counting procedures were applied to estimate quantitative tissue and cytoplasm parameters of the oral and the junctional epithelium of the human gingiva. Three gingival biopsies of female children, obtained and processed under standardized conditions, served (1) to determine the minimal sample size of cytoplasmic area required for estimating representative volumetric parameters in different strata of both epithelia, and (2) to compare average volume and surface density data derived from standardized samples in epithelial cross sections cut at two planes orientated perpendicular to each other. Sampling of electron micrographs, performed at two levels of magnifications according to a systematic stratified random sampling procedure consisted of recording field strips parallel to the epithelial or tooth surface within each of the various strata. The optimal sample size required varied for different organelles and epithelial strata. Minimal sample size of cytoplasmic area per biopsy were 300–440 μm² for basal, and 450 μm² for stratum spinosum cells of oral epithelium, and 130–185 μm² for basal cells of the junctional epithelium. Average morphometric parameters for gross tissue components (cells, nuclei, cytoplasm, intercellular space) which resulted from analysing 4900 μm² tissue area in each of the epithelia in each biopsy, were almost identical when determined in two different section planes. Volume and surface density data of cytoplasmic organelles (mitochondria, rough and smooth endoplasmic reticulum, cytoplasmic filaments) resulting from a sample of 280 μm² cytoplasmic area per stratum and biopsy, revealed differences of varying magnitude, when determined in the two section planes. These differences were markedly smaller than those between comparable strata of both epithelia. Discussion of sampling procedures concluded that the type of sampling used for the present study is suitable for comparative morphometric studies.     

Form und Intensität des Termitenangriffes an Hölzern verschiedener Struktur und Rohdichte Erste Mitteilung: Prüfungen an getrenntem Früh und Spätholz

Zusammenfassung An getrenntem Frühholz und Sp?tholz der Holzarten Kiefer, Fichte und Stieleiche wurden Fra?zwangsversuche mit der BodentermiteReticulitermes lucifugus Rossi durchgeführt. Es wurde beobachtet, da? die Termiten beim Holzangriff vornehmlich Radialfl?chen bevorzungen und in tangentialer Richtung weiterfressen. Der Holzabbau von Frühholz und Sp?tholz nimmt mit ansteigender Rohdichte ab.

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The way and intensity of termite attack on wood of different structure and density—Part I: Tests with separated spring: and summerwood

Summary Separated samples of springwood and summerwood of the species Scots pine, spruce and pedunculate oak were exposed to the attack of the soil-termite Reticulitermes lucifugus Rossi. When termites attack wood they mainly prefer radial sections and are going foreward in tangential direction. The portion of destroyed spring- and summerwood decreases when density increases.

     

Bücherschau

Ohne Zusammenfassung VDI