Sorsa T, Uitto V-J, Suomalainen K, Vauhkonen M, Lindy S.: Comparison of interstitial coliagenases from human gingiva, sulcular fluid and polymorphonuclear leukocytes. J Periodont Res 1988: 23: 386-393. Mammalian coliagenases (EC 3.4,24,7) have been suggested as playing an essential role in the initiation of the collagen degradation in periodontal diseases. Two distinct types of interstitial coliagenases have been characterized in vertebrate tissues. These enzymes, the fibrobiast-and the neutrophil-type coliagenases,, differ in molecular weight and antigenic properties, as well as substrate specificity and mechanism of activation. In order to determine the cellular origin and mode of action of coliagenase in periodontal tissue, we studied the molecular size, the substrate specificity and the activation of coliagenases partially purified from inflamed human gingival extracts, sulcular fluid, gingival expiant culture medium and polymorphonuclear leukocytes (PMN). Types I, II and III collagens used as substrates were purifted from bovine tendon, cartilage and amnion membrane, respectively. Apparent molecular weights of 70-75 k were obtained for gingival extract, sulcular fluid and PMN coliagenases and 45 k for gingival expiant culture collagenase by gel filtration technique. The gingival extract and sulcular fiuid coliagenases as well as PMN collagenase could be activated by gold thioglucose and gold thiomalate; no activation of gingival expiant culture collagenase was noted. The gingival extract collagenase. sulcular fluid collagenase and PMN collagenase degraded preferentially types I and 11 collagens relative to type-Ill collagen. In contrast, gingival expiant culture coliagenase degraded preferentially types I and III collagens relative to type-II collagen. The results indicate that collagenase in extracts of inflamed human gingiva and in sulcular fluid during inflammation is mostly derived from PMN cells. On the other hand, collagenase produced by gingival explants in culture is probably synthesized by fibrobiasts.

The diagnosis of atrophic gastritis obtained with the blood test panel of S-G-17, S-PGI and H. pylori antibodies is in good agreement with the endoscopic and biopsy findings. The panel is a tool for non-endoscopic diagnosis and screening of atrophic gastritis.

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The lateral organization of fluid cholesterol-dimyristoylphosphatidylcholine (DMPC) bilayers was studied by measuring the response of fluorescent membrane probes, dipyrenylphosphatidylcholines (diPyrxPCs) or merocyanine 540, to the variation of cholesterol concentration. Parallel absorbance and light-scattering measurements were also carried out. The excimer-to-monomer ratio of diPyrxPCs displayed abrupt deviations at particular cholesterol mole fractions (CMFs). The most notable of these occurred at CMFs of 0.15, 0.33, and 0.67. Deviations were also frequently observed at CMFs of 0.12, 0.20, 0.25, and 0.40. Merocyanine 540 reproducibly reported deviations at CMFs of 0.15 and 0.33 and frequently reported values close to 0.12, 0.20, and 0.25. In absorbance (turbidity) and light scattering versus CMF plots, well-defined kinks were observed at CMFs of 0.16, 0.33, 0.52, and 0.67. The occurrence of kinks or other deviations at those particular CMFs is most readily explained in terms of a superlattice model previously developed to explain the lateral distribution of pyrenylphospholipids in bilayers [Somerharju, et al. (1985) Biochemistry 24, 2773-2781; Virtanen, J. A., et al. (1988) J. Mol. Electron. 4, 233-236]. This model is based on the assumptions that (i) each cholesterol molecule replaces a single acyl chain in a hexagonal lattice, (ii) cholesterol molecules, because of their larger size, perturb the lattice, (iii) this perturbation is minimized when the cholesterol molecules are maximally separated from each other, and (iv) the maximal separation is achieved when the cholesterol molecules form a hexagonal or centered rectangular superlattice. All detected critical CMFs, except that at CMF 0.67, are predicted by the model, thus strongly supporting its validity. The critical CMF at 0.67 is a limiting case, which can be accounted for by assuming that cholesterol and phospholipid molecules form alternating rows, i.e., formation of a cholesterol superlattice with rectangular symmetry. As predicted by the superlattice model, composition-driven order-to-disorder transitions occur between the critical CMFs, as indicated by increased data scatter and sample fluctuations in those regions. Another important prediction of the superlattice model is that domains with different cholesterol superlattices should coexist at most cholesterol concentrations. Such domains do not have to be extensive to account for the critical events observed here; rather, they are expected to be dynamic entities of limited size. It is very likely that such microscopic domains with distinct cholesterol superlattices also coexist in biological membranes. This is expected to have remarkable effects on both the structure and functions of these membranes.