The interaction of platelets and von Willebrand factor (vWF) in platelet-type von Willebrand's disease (vWD) was characterized using formalin-fixed platelets from the patients. Formalin-fixed patient platelets were agglutinated directly by human vWF in normal plasma and type IIB vWD plasma, but not in type IIA vWD plasma. In the presence of a small amount of normal vWF, ristocetin-induced agglutination of patient platelets was enhanced with low concentrations of ristocetin. Wheat germ agglutinin and EDTA inhibited vWF-induced agglutination, although EDTA had no effect on ristocetin (plus vWF)-induced agglutination. These results demonstrate that vWF-induced agglutination of platelet-type vWD platelets is independent of active platelet metabolism but requires divalent cations, and suggest that platelet membrane glycoprotein I (GPI) would be involved in this agglutination.

Blood Coagulation Factors↗

PubMed1984

[A study on salivary peptide P-C with special reference to intracellular localization of salivary peptide P-C like immunoreactivity in the human pancreatic B-cells].

In order to clarify the intracellular localization of salivary peptide P-C like immunoreactivity in the human pancreatic B-cells, an immuno-electronmicroscopical study using protein A-gold technique was carried out on the human foetal pancreas. Salivary peptide P-C like immunoreactivity was present in some of insulin secretory granules while insulin like immunoreactivity was found in all insulin secretory granules. The finding suggested that new substance in addition to insulin and its precursor was present in the insulin secretory granules of the human pancreatic B-cells. Furthermore, the finding seemed to explain the previous study that development of salivary peptide'P-C like immunoreactivity in the foetal pancreatic B-cells was immature in compared to that in the human adult pancreatic B-cells. In addition, to examine whether or not, salivary peptide P-C like immunoreactivity in the human pancreatic B-cells is Salivary Protein C, an indirect immunofluorescence technique using three kinds of antisera against salivary peptide P-C, Salivary Protein C and salivary peptide P-B, and using their antigens was undertaken on the adult pancrease. From the results of the study, it was thought that salivary peptide P-C like immunoreactivity in the human pancreas was neither Salivary Protein C itself, nor salivary peptide P-B itself, but was either salivary peptide P-C itself or unknown substance which had the common antigenic determinant with salivary peptide P-C, P-B and Salivary Protein C, since salivary peptide P-C like immunoreactivity in the human pancreas disappeared in the sections in which P-C antisera preincubated with each of salivary peptide P-C, P-B and Salivary Protein C were used as the primary antisera. Thus, although new substance was present in the insulin secretory granules of the human pancreatic B-cells, its pathophysiological role remained to be elucidated.

Cytoplasmic Granules↗

PubMed1984

Anesthetic-protein interaction. Random versus helix polylysine monolayers and interaction with 1-alkanols.

Penetration of 1-alkanols into monolayers of hydrophobic polypeptides, poly(epsilon-benzyloxycarbonyl-L-lysine) and poly(epsilon-benzyloxycarbonyl-DL-lysine), was compared with their adsorption on the air/water interface in the absence of monolayers. The polypeptide prepared from L-lysine is generally considered to be in the alpha-helical form whereas DL-copolymer polypeptide contains random-coiled portions due to the structural incompatibility between the two isomers. The free energy of adsorption of 1-alkanols on the air/water interface at dilute concentrations was -0.68 kcal X mol-1 per methylene group and 0.15 kcal X mol-1 for the hydroxyl group at 25 degrees C. In the close-packed state, the surface area occupied by each molecule of 1-alkanols of varying carbon chain-lengths showed nearly a constant value of about 27.2 A2, indicating perpendicular orientation of the alkanol molecules at the interface. About 75% of the water surface was covered by 1-butanol in this close-packed state. The mode of adsorption of 1-alkanols on the vacant air/water interface followed the Gibbs surface excess while the mode on the polypeptide membranes followed the Langmuir adsorption isotherm, indicating that the latter is characterized by the presence of a finite number of binding sites. The free energies of adsorption of 1-alkanols on the L-polymer monolayers were more negative than those on the vacant air/water interface and less negative than those on the DL-copolymer monolayers. Thus, the affinity of 1-alkanols to the interface was in the order of vacant air/water interface less than L-polymer less than DL-copolymer. The difference between the air/water interface and L-polymer was about 0.54 kcal X mol-1 and that between L-polymer and DL-copolymer was 0.17 kcal X mol-1 at 25 degrees C: the adsorption of 1-alkanols to the DL-copolymer was favored compared to the L-polymer. The polar moieties of the backbone of the DL-copolymer may be exposed to the aqueous phase at the disordered portion. Dipole interaction between this portion and 1-alkanol molecules may account for the enhanced adsorption of the alkanols to the DL-copolymer.

Adsorption↗

PubMed1984

Platelet aggregation induced by DDAVP in platelet-type von Willebrand's disease.

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Arginine Vasopressin↗

PubMed1984

[A study on salivary proline-rich peptide P-C with special reference to the presence of salivary peptide P-C in the human respiratory tract].

In order to elucidate whether Salivary Protein C and salivary peptide P-C, originally isolated from human saliva were present in tissues other than those of the salivary glands or not, an indirect immunofluorescence technique using both antisera against salivary peptide P-C and Salivary Protein C was carried out on human salivary glands and the human respiratory tract. As salivary peptide P-C-like immunoreactivity was detected in the serous cells of salivary glands by previous immunohistochemical study, the human respiratory tract was closed as model tissue, since tracheal and bronchial glands in the human respiratory tract consist of mucous and serous cells. Furthermore, to check whether salivary peptide P-C is a fragment of Salivary Protein C or not, the same immunohistochemical study was undertaken on the serial sections of salivary glands and the respiratory tract. Salivary peptide P-C and Salivary Protein C-like immunoreactivities were present in the serous cells of human salivary glands and in tracheal and bronchial cells. Furthermore, the same serous cells were immunostained with antisera against salivary peptide P-C, with antisera against Salivary Protein C and with antisera against Salivary Protein C preabsorbed with salivary peptide P-C. In view of the fact that the full sequence of salivary peptide P-C is identical to the COOH terminal 44 amino acid residues of Salivary Protein C, it was suggested that the full sequence of Salivary Protein C was present in the serous cells of human salivary glands and in those of tracheal and bronchial glands and that salivary peptide P-C was a fragment of Salivary Protein C.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchi↗