X-RAY DIFFRACTION STUDIES ON AMYLOID FILAMENTSEANES, E. D.; GLENNER, G. G.
doi: 10.1177/16.11.673pmid: 5723775
The filamentous protein component of amyloid-laden tissue was studied by x-ray diffraction procedures. The principal features of the x-ray pattern from nonoriented amyloid material consist of a sharp, intense ring at 4.75 Å overlaying a diffuse halo at 4.3 Å, and a broad and less intense ring at 9.8 Å. When oriented, the material gives a "cross-β" x-ray pattern. The x-ray findings are interpreted in terms of a "pleated sheet" structure formed by the amyloid polypeptide chain folding in a regular manner on itself such that adjacent chain segments are laterally arranged in an antiparallel manner. The x-ray patterns from oriented amyloid suggest further that the axes of the chain segments run transverse to the filament axis.
LOCALIZATION OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN PRENEOPLASTIC AND CANCEROUS CELLS OF THE MOUSE SKIN INDUCED BY METHYLCHOLANTHRENESUGÁR, JÁNOS; CSUKA, ORSOLYA; TÓTH, JÓZSEF
doi: 10.1177/16.11.678pmid: 4235543
The localization of membrane-bound adenosine triphosphatase activity has been studied by both light and electron microscopy in the normal epidermis and in methylcholanthreneinduced preneoplastic alterations, i.e., hyperplasia, papilloma and also in similarly induced cancers of the skin of mice. In normal epidermis, the adenosine triphosphatase activity was seen to be located in contact with all of the cell membranes facing the intercellular spaces. In preneoplastic alterations, the enzyme activity was found along the cell membranes of the basal and suprabasal cells of the epithelial pegs and numerous dense deposits of lead phosphate could be seen on the surfaces of the cytoplasmic processes and in the enlarged intercellular spaces. The intensity of the reaction in preneoplastic conditions was greater than in the normal epidermis. No adenosine triphosphatase activity was observed in the cell membranes facing the basement membrane or in the desmosomes. In carcinoma a less intensive adenosine triphosphatase reaction was present and could be recognized on the surface of only few tumor cells.
HYALURONIDASE ACTIVITY OF ALVEOLAR MACROPHAGESGOGGINS, JOHN F.; LAZARUS, GERALD S.; FULLMER, HAROLD M.
doi: 10.1177/16.11.688pmid: 5723776
Hyaluronidase activity was detected in preparations of isolated rabbit lung alveolar macrophages. The enzyme manifested a pH optimum of 3.9 with no activity detected above pH 5. Analysis of reaction products isolated from digests containing low enzyme concentrations revealed the production of large oligosaccharides from hyaluronic acid without the liberation of free N-acetylglucosamine or glucuronic acid. On the other hand, smaller oligosaccharides and free N-acetylglucosamine were obtained from digests with high concentrations of the crude enzyme. These data in conjunction with the findings of others indicate that macrophages contain hyaluronidase and other enzymes active against polymerized hyaluronic acid and its digestion products.
CYTOPHOTOMETRIC DETERMINATION OF ALKALINE PHOSPHATASE ACTIVITY OF INDIVIDUAL NEUTROPHILIC LEUKOCYTES WITH A BIOCHEMICALLY CALIBRATED MODEL SYSTEMVAN DER PLOEG, M.; VAN DUIJN, P.
doi: 10.1177/16.11.693pmid: 5723777
A model system consisting of polyacrylamide films into which cell sonicate is incorporated was applied to investigate quantitative aspects of the cytochemical azo dye coupling method for alkaline phosphatase activity in neutrophilic leukocytes. The films were assayed in media containing naphthol AS-MX phosphate and 4-aminodiphenylamine diazonium sulfate. Optimal reaction conditions under which proportionality existed between the amount of reaction product and incubation time or enzyme concentration were determined. Since the enzyme activity in the films could also be measured chemically, using disodium phenyl phosphate as a substrate, a direct relation between the cytochemical and biochemical activity could be established. The azo dye coupling method was applied for the quantification of the enzyme activity. Air-dried microscopic preparations of exudate neutrophils were stained and the amount of dye formed in the cytoplasm of individual leukocytes was measured with a cytospectrophotometer based on the two-wavelength principle. By reference to the relation between biochemical and cytochemical activities in the model films, the cytochemically determined enzyme activity could be expressed in biochemical units. Independently, the average alkaline phosphatase activity per cell was determined by direct biochemical assay of the leukocyte suspension. The results showed that about 60% of the biochemically assayed activity in sonicate was demonstrated in the cell preparations by the cytochemical staining method. The discrepancy between the results of the two methods is discussed. The applicability of the model system for elucidation of the relationship between the results of cytochemical and biochemical enzyme determination in cells is stressed.
STRUCTURAL CHANGES OF ISOLATED RAT PERITONEAL MAST CELLS INDUCED BY ADENOSINE TRIPHOSPHATE AND ADENOSINE DIPHOSPHATEDIAMANT, BERTIL; KRÜGER, PER GÖRAN
doi: 10.1177/16.11.707pmid: 4177662
Procedures for the local application of chemical agents to individual rat peritoneal mast cells are described. The local application of adenosine triphosphate (ATP) to the mast cell surface did not induce degranulation of the cell, a process known to occur concomitantly with histamine release induced by compound 48/80 and antigen-antibody reactions. Instead, reversible configurational changes of the cell membrane gradually occurred without any striking changes in the over-all cell volume. Swelling was observed after incubation of mast cells with ADP as well as by intracellular electrical manipulations with pipettes filled with H3PO4. The reversal of swelling was also demonstrated. The results are discussed in relation to the known histamine-releasing effect of ATP on rat mast cells and the difference in the mechanisms of histamine release induced by ATP and degranulating agents are stressed.