Mechanism of inhibitory effect of dextran sulfate and heparin on human T-cell lymphotropic virus type I (HTLV-I)-induced syncytium formation in vitro: role of cell-to-cell contact.

Cell-to-cell contact is usually essential for syncytium formation by HTLV-I-infected cell lines. The present study was undertaken to determine the inhibitory effect of polyanionic compounds, dextran sulfate and heparin, on HTLV-I-induced syncytium formation, as demonstrated by the fusion of HTLV-I-infected cells with target cells. These two compounds almost completely blocked syncytium formation in the early phase of the reaction at a concentration of 125 micrograms/ml, but dextran, as a control, did not inhibit it at concentrations up to 625 micrograms/ml. 50% inhibition of syncytium formation was detected at a concentration of 2 micrograms/ml of dextran sulfate 5000, 3 micrograms/ml of dextran sulfate 8000 and 8 micrograms/ml of heparin. The binding of radiolabeled HTLV-I-infected cells (HCT-1) to the target cells was inhibited by addition of dextran sulfate and heparin, and the inhibitory effects were concentration-dependent. No marked changes were detected in the expression of adhesion molecules on the virus-infected cells and target cells, and in the expression of envelope proteins on the virus-infected cells after exposing them to the polyanionic compounds. These results suggest that the blocking of cell-to-cell contact by polyanionic compounds, probably independent of surface adhesion molecules, is important for their inhibitory effect on HTLV-I-induced syncytium formation.

[Preoperative embolization for meningiomas using PVA particles].

Preoperative embolization for highly vascularized and large meningiomas is an indispensable technique for facilitating their surgical removal by decreasing blood loss during the operation. This is a report of 4 large and highly vascularized meningiomas in the skull base, on which embolization of feeders was performed preoperatively by PVA (Polyvinyl alcohol foam) particles (150-250 micron produced by INGENOR CO, Paris) and small strips of gelfoam (0.5 x 0.5 x 3-5mm). Under EEG monitoring, Isosorbide dinitrate was used for prevention and relief of vascular spasm. Lidocaine injection tests (Xylocaine 2%: 50mg mixed in equal volumes with Iopamiron 300) were performed for checking before embolization. In the intracranial portion, standard taper steerable guide wire was changed to seeker flexible soft-tip guide wire. In two cases, the meningioma was located in the medial part of the sphenoidal ridge. In the other two cases, one meningioma was in the lateral part of the sphenoidal ridge and the other was in the olfactory groove. In all 4 cases, we successfully performed embolization without complication. In one case, we had to perform embolization twice, because of revascularization detected by angiography 3 weeks after the first embolization. In this latter case, we had performed central embolization only, by using PVA particles, having left feeder without occlusion (peripheral embolization) using gelfoam. The result suggested that it was also necessary to perform peripheral embolization especially if the tumor is fed by large tortuous and irregular abnormal vessels. Peripheral embolization may prevent PVA particles from washing out and causing progressive thrombosis by PVA particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of bone matrix protein messenger ribonucleic acids in human breast cancers. Possible involvement of osteopontin in development of calcifying foci.

BACKGROUND: Development of calcifying foci is a fairly common finding in human breast cancers, and the deposition of calcium phosphate is observed in such foci. The calcium phosphate is a physiologic component of bones and teeth. Since the expression of messenger (m) RNAs of osteopontin (OPN), osteocalcin (OC), osteonectin (ON), and matrix gla protein (MGP) has been described in bones and teeth, we examined the mRNA expression of OPN, OC, ON, or MGP in the calcifying foci that were observed in human breast cancers. EXPERIMENTAL DESIGN: Cell types expressing mRNAs of OPN, ON or MGP were identified with combination of in situ hybridization and immunohistochemistry. RESULTS: The OPN mRNA-expressing cells clustered around the necrotic foci within cancer cell nests, and the examination with anti-OPN antibody revealed that OPN protein was localized in such necrotic foci where calcium phosphate deposited. The OPN mRNA-expressing cells were identified as macrophages by staining the adjacent section with the anti-CD68 PG-M1 monoclonal antibody which specifically recognizes macrophages. Neither ON mRNA-expressing cells nor MGP mRNA-expressing cells appeared to correlate with the deposition of calcium phosphate. CONCLUSIONS: The OPN protein produced by macrophages appeared to play a significant role for development of calcifying foci within necrotic area of breast cancers.