[Two cases of myeloid sarcomas with review of literature]. / Sarcome granulocytaire : à propos de 2 cas et revue de la littérature.

INTRODUCTION: Myeloid sarcomas are uncommon proliferations of immature myeloid cells occurring in any extramedullary organ. We report here two cases of myeloid sarcomas in patients with, respectively, a polycythemia vera and a myelodysplastic syndrome. CASE REPORTS: The first is an 81-year-old woman who presented with osteolytic lesions. Diagnosis has been highlighted using anatomopathological study after bone marrow biopsy, but it was delayed because of a very localized basin lesion and few positive myeloid markers. The second patient is an 86-year-old man who presented with pancytopenia and several lymph nodes. Lymph node cytology failed because of the rarity of blast cells. Diagnosis was done after anatomopathological study on lymph node biopsy which revealed a localized form of myeloid sarcoma. CONCLUSION: The diagnosis of myeloid sarcoma must be considered when unusual tumors occur in patients with a chronic myeloid disease. In that case, therapeutic options are those of an acute myeloid leukemia.

Isolation and structural properties of a high-molecular-weight actin-binding protein (filamin-like protein) in hog thyroid gland.

A high-molecular-weight protein has been isolated from hog thyroid gland. This protein, with a molecular weight of 475,000 determined by ultracentrifugation and gel filtration, is a complex of two polypeptides with apparent molecular weights of 250,000 and 240,000. It may be related to filamin-like proteins by its physicochemical properties and its immunogenic cross-reactivity towards gizzard filamin antibodies. Furthermore it interacts with F-actin in a stoichiometry of 1 mol of high-molecular-weight protein/approximately 12-14 mol actin monomer allowing microfilament association, as shown by electron microscopy.

Interaction of yeast 3-phosphoglycerate kinase with negatively charged carriers.

The aim of this study was to investigate the possibility of an interaction of yeast 3-phosphoglycerate kinase with negatively charged carriers such as polyanionic agents or a polarized electrode. Various polyanions were found to promote enzyme aggregation as judged by ultracentrifugation measurements and chemical modification. The data obtained suggest that these interactions are mediated through the N-terminal domain of the protein. However, the most striking property of 3-phosphoglycerate kinase described here is concerned with its significant dipolar moment as evidenced by electrocapillary measurements, which allows an orientation of the macromolecule in an electric field. Further, the enzyme could be absorbed by a negatively charged surface, first by hydrophobic links and then oriented perpendicularly to the surface. Therefore, the intrinsic properties of yeast 3-phosphoglycerate kinase agree with the formation of an enzyme-membrane complex and afford the ability for a specific orientation of the molecule at the lipid bilayer surface or in the cytoplasm.

Yeast 3-phosphoglycerate kinase: sulfate and substrate binding, their effect on the conformational state of the enzyme.

Anions and particularly sulfate are known to interact with 3-phosphoglycerate kinase and to induce an increase of its catalytic efficiency. The present work affords information on the location of the anionic site and on the conformational change produced by the sulfate binding. We have established that sulfate is able, first, to modify the environment of some critical amino acids (cysteine and arginines) located in the N-terminal half of the protein, second, to induce perturbation of aromatic residues as judged by spectrophotometry, and, third, to slightly decrease the magnitude of the Cotton effect at 233 nm. All these modifications are produced by sulfate concentrations required for the activation of the enzyme. The most striking result consists in a large change in the hydrodynamic properties of the protein upon sulfate interaction as determined by analytical ultracentrifugation studies. Thus, sulfate modifies the shape of the molecular, causing it to become more compact. Furthermore, a study of the binary and ternary complexes between yeast 3-phosphoglycerate kinase and its substrates suggests that such a change of the shape of the molecular only occurs in sulfate-enzyme with or without substrates and in ATP (with or without Mg2+)-3-phosphoglycerate-enzyme complexes.