Search

Effects of electromagnetic stirring on the solidification structure of continuously cast SUS430 slabs were investigated to reduce the ridging of cold-rolled sheets by grain refinement of the solidification structure. The following results were obtained:(1) The area in which equiaxed crystals form increases with increasing stirring intensity and decreasing superheat (ΔT) of molten steel. The most suitable stirring mode is the alternate stirring. The effect of ΔT can be moderated by lowering the position of the stirrer, but the ratio of equiaxed crystals decreases in this case. Appropriate conditions for obtaining a ratio of equiaxed crystals over 60% were determined.(2) Ridging is reduced as the ratio of equiaxed crystals increases. Stable ridging obtained for 50% or more equiaxed crystals is the same as that of steel sheets rolled from ingots.

Human B lymphoblastoid line, SKW 6-4, cells were induced to IgM-secreting cells by high concentrations of interleukin 2 (IL 2). These cells were found to be unreactive with anti-Tac antibody and did not express mRNA detectable for Tac antigen. In Scatchard plot analysis, low-affinity IL 2-binding sites were found on SKW 6-4 cells. Moreover, analysis of the IL 2-binding molecules revealed ones (molecular weight 70,000 and 75,000) distinct from Tac antigen. It is conceivable that IL 2 exerts its effect through its interaction with these novel IL 2-binding molecules in SKW 6-4 cells.

Three potent anticancer drugs, mitomycin C (MMC), adriamycin (ADR) and carboquone (CQ), were microencapsulated with ethylcellulose in the principles of coacervation with certain modifications and the microcapsules thus prepared were examined with the scanning electron microscope. It was demonstrated in vitro and in vivo experiments that the release of action of microencapsulated MMC was made sustained and long lasting. The in vitro release of ADR and CQ from the microcapsules was also examined.

Hyperthermic treatment for bladder tumor in the rabbit was investigated by the irrigation with hot saline through cystostomy after the transplantation of V2 carcinoma cells. When the bladder was irrigated with 42-44 degrees C saline, the inhibitory effect on transplanted tumor growth in the urinary bladder was significant in comparison with control groups. Antitumor effect on the survival and changes in body weight were also significant. Histological study showed the tumor cells were more susceptible to heat than normal mucosal layer. The results suggest that the hyperthermic irrigation of the urinary bladder was effective in preventing the tumor growth with minimum damage on the normal bladder mucosa. Moreover, this malignant bladder tumor of rabbit seems especially suitable for the purpose of studying the new method for transurethral hyperthermic treatment of the urinary bladder cancer.

Chinese hamster ovary (CHO) cells were transfected with a human interleukin 4 (IL-4) expression plasmid in which human IL-4 cDNA is linked downstream of the human cytomegalovirus/human immunodeficiency virus chimeric promoter. The plasmid also contained a mouse dihydrofolate reductase (dhfr) gene, expression of which is directed by the SV40 early promoter. The resulting methotrexate-resistant, transformed cells constitutively secreted a high level of human IL-4. CHO cells producing human IL-4 were cultured on microcarriers in a perfusion cell culture system containing 1 l of culture medium, and a high level of human IL-4 (5 × 10 4 U ml −1 ) was produced at a high cell density (1 × 10 7 cells per ml). Serum-free culture was also examined.

Ethylcellulose microcapsules of mitomycin C were prepared for intra-arterial use in an attempt to enhance the antineoplastic effects of mechanical arterial embolization. The potential therapeutic effects of intra-arterial mitomycin C microcapsules were considered to be a function of microembolization and prolonged drug action, that is chemoembolization. A total of 33 patients with renal cell carcinoma was subjected to transcatheter arterial chemoembolization with mitomycin C microcapsules supplemented with gelatin sponge, and 10 patients were subjected to chemoembolization with non-encapsulated mitomycin C and gelatin sponge. Comparative studies on objective tumor decrease, angiographical findings and histological effects between the 2 treated groups indicated that mitomycin C microcapsules definitely enhanced the therapeutic responses to gelatin sponge embolization. Bioassay of the peripheral blood revealed that intra-arterial mitomycin C microcapsules reduced markedly mitomycin C levels in the blood compared to non-encapsulated mitomycin C, leading to a decrease in hematological toxicity. The results may prove that chemoembolization with mitomycin C microcapsules is effective as a preoperative and palliative measure in the treatment of renal cell carcinoma.

Mitomycin C (MMC) was microencapsulated with ethylcellulose. The microcapsules contained, on average, 80% of biologically active MMC and had a sustained-release property. The mean particle size was 224 micrometers so that the microcapsules were readily infused into a canine kidney through arterial catheterization. Ex vivo infusion demonstrated that the microcapsules lodged in the small arteries, mainly at the cortico-medullary junction, and released concentrated MMC into the surrounding tissue. In vivo experiments revealed that the canine kidneys infused with the microcapsules retained active MMC for more than 6 hours and showed extensive necrosis five days after the infusion. The kidneyks infused with nonencapsulated MMC rapidly excreted MMC and showed mild histologic changes. The blood level of MMC released from the intrarenal microcapsules was markedly reduced as compared with control levels. The results suggest that the potential therapeutic effect of intraarterial infusion of MMC microcapsules is a function of embolization and prolonged drug action, and that selective infusion of MMC microcapsules into tumor-supplying arteries could facilitate intensive topical chemotherapy with minimum systemic side-effects.

To improve dephosphorization of hot metal by the lime injection process, it is necessary to clarify the dissolution mechanism of blown-in CaO in hot metal, the mechanism o f dephosphorization reaction and the region where the reaction takes place. For this purpose, a single-crystal lime lump immersion test and a lime powder injection test were made. Lime lumps after immersion tests, reaction products adhered to Al2O3 tubes immersed into hot metal and collected slag samples by steel samples were analyzed by EPMA.In hot metal, CaO starts to dissolve due to penetration o f FetO and MntO. Then, the dephosphorization reaction initiates between {CaO-Fe (Mn)tO}l and phosphorus, and the latter is fixed as (CaO-SiO2 P2O5)s in the reaction layers. Dephosphorization takes place mainly in the vicinity of the oxygen blowing nozzle.The slagging rate of solid CaO decreases with increasing distance between the nozzle and the suspending position of CaO since carbon in hot metal consumes oxygen. The dephosphorization rate also decreases with increasing distance since FetO in {CaO-Fe (Mn)tO}l is reduced by carbon.It is concluded that the increases both in the slagging rate of solid lime and oxygen potential in the bath is necessary to enhance the dephosphorization rate and in this sense, the injection of iron oxide with oxygen is effective.

NEMOTO, R., SHINDO, M., MORI, H., ABE, R. and KATO, T. Intravesical Chemotherapy of Urinary Bladder Tumor in Rabbit by Ferromagnetic Mitomycin C. Tohoku J. exp. Med., 1983, 139 (3), 315-320 -Considering the necessity of selective toxicity in cancer chemotherapy, an advantageous means of controlling the anticancer agent in the urinary bladder was facilitated by microencapsulation of the drug and ferrite particles. Pharmacokinetic analysis of intravesical instillation chemotherapy in rabbits proved that magnetic control of ferromagnetic microencapsulated mitomycin C (MMC) remarkably enhanced MMC absorption into the urinary bladder wall. Moreover, malignant bladder tumors in rabbits were successfully treated with this method.

The functional, high affinity form of interleukin-2 receptor (IL-2R) is composed of two receptor components, the IL-2R alpha (p55) and IL-2R beta (p70-75) chains. Unlike the IL-2R alpha chain, the IL-2R beta chain contains a large cytoplasmic domain that shows no obvious tyrosine kinase motif. In the present study, we report the establishment of a system in which the cDNA-directed human IL-2R beta allows growth signal transduction in a mouse pro-B cell line. This system enabled us to identify a unique region within the cytoplasmic domain of the human IL-2R beta chain essential for ligand-mediated signal transduction. We also demonstrate that certain cytoplasmic deletion mutants in the IL-2R beta chain, although deficient in signal transduction, can still form high affinity IL-2R in conjunction with endogenous mouse IL-2R alpha chain; the mutants are still able to internalize the ligand as well.

Ferromagnetic microcapsules (FM-mc.) were prepared with ethylcellulose according to the principles of coacervation with certain modification. The zinc ferrite (ZnO·Fe2O3) particles were attached to surface of microcapsules. Sustained-release of FM-mc. was demonstrated by release test and it can be induced by an external magnetic field in vitro and in vivo experiments.

The acoustic Emission Characteristics are investigated for various failure modes (such as fibre breakage, matrix crazing and delamination) of Boron reinforced Aluminum Composites materials. Tensile Tests are conducted for specimens of four kinds of type (unidirectional, 0°/90° ply, boron fibre and shear lag test pieces). The results show that A. E. Characteristics (count rate, amplitude distribution and location) are different with failure modes. A. E. amplitude is above 90 dB for the fibre breakage of unidirectional ply test piece but below 90 dB for the transverse one of cross ply, which fractured at low level load, while the shear lag test pieces produce acoustic emission amplitude in the range of 40∼60 dB under delamination fracture mode.

Phase separation method has been applied to improve efficiency of magnetic control of ferromagnetic microcapsules. Ferromagnetic mitomycin C microcapsules (FM-MMC-mc.) were prepared by enclosing minimum ferromagnetic ferrite in mitomycin C microcapsules. On the other hand, FM-MMC-mc. was injected into the bladder of rabbits to treat the experimental bladder cancer which had been produced by transplanting V 2 carcinoma. As a result, antitumor effect of FM-MMC-mc. was remarkably higher fhan that of injectable MMC as control. Thus, the efficacy of FM-MMC-mc. was confirmed in this study.

Trace amounts of manganese in steel was determined nondestructively by neutron activation analysis using the JRR-1 reactor (neutron flux: 1O/sup 11/n/cm/ sup 2/ - sec). The induced radioactivity of Mn/sup 56/ was measured with a well type scintillation counter and a gamma spectrometer. The agreement between neutron activation analysis and chemical analysis was within plus or minus 10%. The relative error due to counting fluctuation was 2% for 0.01 r of manganese (2 hr irradiation). In order to eliminate the influence due to the activity of Cu/ sup 64/, manganese activity was counted from 1 to 5 hr after the irradiation. (auth)