Interaction between glutathione and the endoplasmic reticulum in cyclic protein synthesis in sea urchin embryos.

Interaction between an oxidoreduction system and cyclic protein synthesis was studied in sea urchin embryos. When assayed enzymatically, in both in vivo and in vitro systems, the contents of GSH and GSSG varied inversely in a cyclic fashion. Diamide at 0.5 mM inhibited amino acid incorporation in not only the cyclic phase but also the basal phase, but 4-nitroquinoline-N-oxide at 1 μM inhibited only the cyclic phase. Sea urchin embryos contained membrane-bound ribosomes, and pulse-labeling with amino acids suggested that free ribosomes were responsible for the basal phase and membrane-bound ribosomes were responsible for the cyclic phase of amino acid incorporation. Thiol-disulfide interchanging enzyme was found in the endoplasmic reticulum fraction. An extract of the endoplasmic reticulm caused stimulation of binding of acetylphenylalanyl-tRNA to 40S ribosomes and polyphenylalanine synthesis in the presence of low GSH concentrations. An extract of the endoplasmic reticulum also catalyzed oxidoreduction from GSH to the KCl-soluble protein. Thus, the periodic stimulation of protein synthesis is interpreted to be the result of the periodic activation of membrane-bound ribosomes by the thiol-disulfide interchanging enzyme which accepts selectively the signal from the GSH cycle.     

Great depth pneumatic caisson and its load work involved with the efficiency of respiratory protection

Pneumatic caisson work in Japan has been in operation since 1924. Afterward, this technique of compressed air work has been utilized in the constructions like as foundation works, the basements, and shafts of the bottom tunnel or shields for subway and so forth. While, it means for people to be exposed to hyperbaric environment that they use compressed air work, this technique has risks to be suffered from not only decompression sickness (DCS) but toxicity of poisonous gas or oxygen deficiency. However, this technique is necessary for urban civil engineering and recent compressed air works over than 1.0 kg/cm2 has been increased in 1.5 times more than in 1970's and the higher compressed air work more than 4.0 kg/cm2 will be actually planned in near future. So unmanned caisson work is considered as a better technique for such high pressure work, even though people must enter into hyperbaric working fields for maintenance or repair of unmanned operated machinery and materials. This research is to establish the safety work under hyperbaric environment within 7 kg/cm2. It is necessary for us to establish the system not only to keep safety but to maintain working efficiency. According to obtain the purpose, the effect of respiratory protection has been investigated and work load under hyperbaric caisson work has also been studied.     

Studies on the behavioral pharmacology of TRH-T in cytosine arabinoside-induced ataxic mice: a comparison with genetically ataxic mice

The effects of thyrotropin releasing hormone tartrate (TRH-T) on the behavior of cytosine arabinoside (Ara-C) induced ataxic mice were studied. The ataxic mice were prepared by injecting 50 mg/kg/day subcutaneously on the 2nd, 3rd and 4th postnatal days. Spontaneous motor activities were measured with a movement spectrum analyzer (ANIMEX-2) and the degree of ataxic gait determined by an open-field study. Cerebella from these animals were subjected to histopathologic examination at 4, 8 and 12 weeks of age. Ataxic gait became improved moderately and spontaneous motor activities increased slightly following administration of TRH-T. The effects of TRH-T on ataxia and spontaneous motility in the Ara-C injected mice varied with the age, and resembled those seen in weaver mice but not those in the Rolling mouse Nagoya. The results also suggest that the effects of TRH-T on the behavior of ataxic mice correlate with the extent of pathologic changes evoked in their cerebella.     

Control of placental protein production by retinoic acid in cultured placental cells

Summary The synthesis of human chorionic gonadotropin (HCG), the subunit of HCG (HCGα), and pregnancy-specific β₁-glycoprotein (PSβG) was studied in temperature senstive (ts), simian virus 40 (SV40)tsA mutant-transformed human first trimenster placental (SPA255-26) cells. Retinoic acid increased the production of HCG and PSβG but inhibited the production of HCGα in these cells. Passage ofSPA255-26 placental cells in medium containing retinoic acid induced a stable altered phenotype characterized by elevated levels of HCG and PSβG and a reduced level of HCGα. The retinoic acid induced phenotypic changes in these placental cells were reversible; removal of retinoic acid immediately decreased the production of HCG and PSβG while increasing the production of HCGα. The ratio of HCG to HCGα in controlSPA255-26 cells was approximately 0.1; this ratio in creased to 4.8 in cells maintained in medium containing retinoic acid. Similarly, the HCG-to-HCGα ratio increased in choriocarcinoma cells maintained in retinoic acid containing medium. Our data suggest that retinoic acid may be needed to maintain a blanced production of HCG, HCGα, and PSβG in placental cells in vitro. Retinoic acid may also play a role in modulating placental protein production during pregnancy.