Vascular endothelial growth factor overproduced by tumour cells acts predominantly as a potent angiogenic factor contributing to malignant progression

To elucidate the role of vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, in tumour angiogenesis and malignant progression, an expression vector harboring human VEGF cDNA was stably transfected into three human cancer cell lines with poor VEGF productivity. Though their in vitro growth rate and intrinsic productivity of another angiogenic factor, basic fibroblast growth factor (bFGF), were not changed by transfection, those clones with higher VEGF production were endowed with tumorigenic and angiogenic potentials as follows: firstly, nontumorigenic, lung carcinoma QG90 cells having lower bFGF productivity acquired tumorigenicity as well as significant in vivo angiogenesis-inducing ability, secondly, tumorigenic colorectal carcinoma RPMI4788 cells having higher potency for bFGF production could form more vascularized solid tumour with faster growth rate and thirdly, oestrogen-dependent breast carcinoma MCF-7 cells, which did not produce detectable bFGF, acquired tumorigenicity even in the absence of oestrogen and the solid tumour growth rate was remarkably enhanced, accompanied with increased vascularization, in the presence of oestrogen. These results suggest that tumour progression closely depends on angiogenesis, and VEGF significantly contributes to malignant progression of a variety of tumour cells through its potent angiogenic activity, independent on the bFGF productivity of tumour cells.     

αN-catenin expression in the normal and regenerating chick sciatic nerve

Summary The Ca²⁺-dependent intercellular adhesion molecule cadherin is known to be linked to the cytoskeleton by the protein catenin, an association of which appears to be important for the cell-adhesion function of cadherin. Catenin consists of three subtypes-, , and . In our previous study, N-cadherin was shown to be localized on the plasmalemma of normal and regenerating chick peripheral nerve. Thus, as N-catenin is a subtype of -catenin (which is specifically associated with N-cadherin), we investigated the immunolocalization of N-catenin in normal and regenerating chick sciatic nerve. In normal nerve, unmyelinated axons exhibited either intense or weak N-catenin immunoreactivity throughout the axoplasm, whereas myelinated axons were completely immunonegative. Regenerating axons, including those derived from parent myelinated axons, showed N-catenin immunoreactivity of variable intensities in growth cones and axon shafts. Schwann cells were invariably devoid of immunoreactivity. Thus N-catenin is not necessarily bound to the surface plasmalemma, but is distributed throughout the cytoplasm, suggesting that most N-catenin molecules are dissociated from N-cadherin.     

Phenotypic modulation in cisplatin-resistant cloned cells derived from transplantable rat malignant fibrous histiocytoma

The histogenesis of malignant fibrous hlstlocytoma (MFH) was studled using clsplatln (CDDP)-resistant MT-R8 and MT-R9 cells derlved from cloned undlfferentiated MT-8 and flbrohlstlocytic MT-9 cells, resoecthfely, which had been established from transplantable rat MFH. CDDP concentrations requlred for 50% suppression of prollferation of MT-R8 and MT-R9 cells were 5.4– and 3.3-fold greater than those of parental MT-8 and MT-9, respectively. MT-R8 and MT-Rg showed the higher positive rates to histimytic lysosomal/ antigenic (ED1 and ED2) markers. The number of a-smoath muscle actin (SMA)-positive cells significantly Increased in MT-RB; SMA-positlve cells were also obsenred in MT-R9, but no difference was seen between MT-9 and MT-R9. MT-R8 and MT-R9 expressed both histiwytic and myofibroblastic phenotypes. However, the histology of subcutaneous tumors induced in syngeneic rats by MT-R8 and MR-R9 did not always reflect their in vitro nature. MT-R8 developed undiffer-entlated sarcomas similar to parental MT-8 tumors. In contrast, MT-R9 induced tumors with polytypic histologies such as the storiform growth pattern, neoplastlc growth of granular cells and myofibroblasts, osteosarcoma-like areas, collagen-rich areas containing well-developed fibroblasts and areas involvlng many lipoblasts. These In vivo observatfons suggest the multidlrectional differentiation of MT-R9 cells. Phenotypic modulation of rat MFH cells seemed to be easily induced by CDDP. A possible histogenesis of MFH was discussed based on the data collected.     

Murine macrophage interleukin-1 release by capsularlike serotype-specific polysaccharide antigens of Actinobacillus actinomycetemcomitans.

Serotype-specific polysaccharide antigens (SPAs) were extracted from whole cells of Actinobacillus actinomycetemcomitans ATCC 29523 (serotype a), Y4 (serotype b), and NCTC 9710 (serotype c) by autoclaving and purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. Y4 SPA induced interleukin-1 (IL-1) release by P388D1 murine macrophages. Polymyxin B had virtually no effect on the release of IL-1. Rabbit anti-murine IL-1 serum strongly suppressed the proliferation of C3H/HeJ mouse thymocytes induced with the culture supernatants of Y4 SPA-stimulated P388D1 cells and a submitogenic dose of concanavalin A. Gel filtration of the culture supernatants of Y4 SPA-stimulated macrophages on Sephacryl S-200 showed that an IL-1 peak at a point corresponding to approximately 16.5 kDa was eluted. The ability of SPAs from strains ATCC 29523 and NCTC 9710 to induce the release of IL-1 was lower than that of Y4 SPA. The IL-1-releasing ability of serotype a and c antigens was enhanced by deacetylation of both polysaccharides, suggesting that acetyl groups of these antigens might hinder the interaction between the antigens and macrophages.     

Identification and differentiation of the human herpes virus group using the PCR method]

Six kinds of human herpes viruses have been identified and classified on the basis of structure and characteristics. We studied the identification and classification of these types using PCR to amplify the virus-specific DNA sequences. This method showed higher sensitivity than the conventional method of virus isolation and culture for HSV and CMV detection. For each positive control, the viral DNA was amplified only when the complementary primers themselves were used. PCR apparently detects only the activated virus, because normal controls were negative when this method was used. Therefore, the present method is thought to closely reflect viral activation and infectious diseases in patients with latent infections.     

Bone bonding behavior of three kinds of apatite containing glass ceramics

We have produced three kinds of apatite-containing glass ceramics of the same chemical composition: MgO (4.6), CaO (44.9), SiO2 (34.2), P2O5 (16.3), CaF2 (0.5) (in weight ratio). They contain different crystal combinations and have different mechanical properties. The first glass ceramic (A-GC) was prepared by heating a glass plate to 870 degrees C. It contains only oxy- and fluoroapatite (35 wt%). The second glass ceramic (A-W-GC), and the third (A-W-CP-GC), were prepared by heating glass powder compacts to 1050 degrees C and 1200 degrees C, respectively. A-W-GC contains oxyapatite and fluoroapatite (Ca10(PO4)6(O,F2] (35 wt%) and beta-wollastonite (40 wt%). A-W-CP-GC contains oxyapatite and fluoroapatite (20 wt%), beta-wollastonite (CaO X SiO2) (55 wt%), and beta-whitlockite (3CaO X P2O5) (15 wt%). The bending strengths of A-GC, A-W-GC, and A-W-CP-GC were 88MPa, 178MPa, and 213MPa, respectively, in air. Rectangular ceramic plates (15mm X 10mm X 2mm) were implanted into a rabbit tibia. Ten and 25 weeks after implantation, the segment of tibia with implant was excised for examination. The segment was held by a special jig and the traction breaking load (failure load) was measured by an autograph. A-GC showed a lower load than A-W-GC and A-W-CP-GC. The loads for A-W-GC and A-W-CP-GC were almost equal. The failure loads did not change significantly between 10 and 25 weeks for any of the materials. The interface was examined by Giemsa surface staining, contact micro-radiography, and SEM-EPMA. Giemsa surface staining and CMR revealed direct bonding between the materials and the bone for all the three materials. SEM-EPMA showed that Si and Mg content decreased, Ca content did not change, and P content increased at the reaction zone between all three glass ceramics and bone. This was observed at 10 weeks, as well as at 25 weeks, after implantation. The reaction zone was narrowest with A-GC, wider with A-W-GC, and widest with A-W-CP-GC.     

Immunochemical and structural characterization of a serotype-specific polysaccharide antigen from Actinobacillus actinomycetemcomitans Y4 (serotype b).

A serotype-specific polysaccharide antigen of Actinobacillus actinomycetemcomitans Y4 (serotype b) was extracted from whole cells by autoclaving. The extract was purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300 columns. The purified polysaccharide antigen formed a single precipitin line with anti-type b serum but not with anti-type a serum and anti-type c serum. The antigen was composed of 43.9% L-rhamnose, 49.1% D-fucose, and a trace amount of fatty acid. Methylation analysis, Smith degradation, and optical rotation data showed that the antigen was a polymer consisting of a disaccharide repeating unit, ----3)-alpha-D-fucopyranosyl-(1----2)-beta-L-rhamnopyranosyl-(1----. In quantitative precipitin inhibition tests, D-fucose and L-rhamnose showed very low inhibition, but the partial hydrolysate of the purified antigen was an effective inhibitor, suggesting that the serotype b specific antiserum recognizes the larger oligosaccharide units.