Tissue culture of human thyroid cancer

Human thyroid cancer cells in the pleural effusion were serially cultivated in vitro. Three kinds of cell lines were established from the same primary culture and were designated as PS, TS and TR lines, respectively. These three have been cultured for 574 days up to May 1, 1968. The cells of PS and TR lines were epithelial-like, whereas those of TS line revealed fibroblastic character. The chromosome numbers of PS and TR lines exhibited the modes near the hypertetraploid region, while TS line showed the mode of hypo-triploid number. Eosinophilic particles which were stained metachromatically by toluidine blue were present in the cytoplasm of these cells. The histochemical findings of the cells of each line were identical with those of thyroid cancer cells in vivo. The cells aggregated by the gyratory culture showed epithelial characters under microscopic observation of the sectioned specimens. The tumors produced in conditoned hamsters demonstrated undifferentiated cancer, which resembled the metastatic thyroid cancer of the patient. Neither collagen nor argentaffine fibers were detected with Van Gieson staining or silver impregenation.</p

Recent Changes to Retirement Benefits in Japan, and Relevant Public Policy Issues

In Japan, employee retirement benefits started as lump-sum severance payments supported by the book reserve internal funds. In the 1970s and 1980s many of them came to rely on outside pension plans for funding. Combined, these dual-type benefit plans function as a substantial source of old-age income for 60-70 percent of all employees working for approximately 90 percent of employers. In addition, they have been important components of Japan's seniority-based labor management and compensation system. They have been used in order to make core employees stay for a long time with a single employer. As long-term employment and seniority-based compensation practices became not very effective, which can clearly be seen with the rising labor distribution rate, retirement benefits constituting compensation plans had to undergo substantial adjustments. Declining returns on pension assets since the 1990s, and increasing benefit obligations on balance sheets under new accounting rules put into effect in 2001 accelerated the revision of benefit plans. The goals of this plan revision are to: (a) reduce benefit obligations, (b) maintain consistency with other compensation plan components which are more based on job content and performance rather than seniority, (c) make employees with short tenure eligible for substantial benefits by alleviating backloading and by preparing individual account under Defined Contribution Plans, and (d) lighten the burden of benefit obligations on the balance sheet of plan sponsors and reduce investment risks. Specifically, such measures as the revision of benefit formula and the introduction of point -based benefits are taken. Further, the numbers of Defined Contribution Plans, Employee Pension Funds returning contract-out portion and Cash Balance Plans, all of which became available under two laws enacted in June 2001, have been increasing. Public policies on retirement benefits must keep pace with these dynamic changes. Especially, protection of benefit rights - vesting, non-forfeiting and funding requirement, is the area which demands serious attention. Another area to be reformed is taxation. The introduction of EET (exempt- exempt-taxable) taxation uniformly applicable throughout various forms of retirement benefits, which is exemplified by Canadian Registered Retirement Saving Plan, should be taken into serious consideration.

Tetraquark particle in the string model

We discuss possibility of the existence of tetraquark states made of four quarks in the string (flux tube) model. The new particle is composed of a diquark and an anti-diquark which are connected by a color flux. It is shown that the vibrational and rotational excited states of the string explain some non-$\bar{q}q$ mesons observed experimentally. Moreover we discuss the decay widths of such tetraquarks with the use of the Schwinger mechanism.Comment: 5 pages, 6 figure