Phospholipid modification retards intracellular transport and secretion of immunoglobulin G1 by mouse MOPC-31c plasmacytoma cells

The intracellular transport and secretion of immunoglobulin G1(IgG1) by mouse MOPC-31C plasmacytoma cells were analyzed from the viewpoint of the roles of phospholipids. The membrane phospholipids were modified by culturing cells in a medium supplemented with choline analogues, N,N'-dimethylethanolamine or N-monomethylethanolamine, and accordingly the membranes were enriched in phosphatidyl-N,N'-dimethylethanolamine or phosphatidyl-N-monomethylethanolamine (Maeda, M., Tanaka, Y. and Akamatsu, Y. (1980) Biochem. Biophys. Res. Commun. 96, 876-881). The modified cells were pulse-labeled with L-[35S]methionine and the secretion of labeled IgG1 was chased. Half of the IgG1 was exported to the extracellular medium 1-1.5 h and 2-3 h after synthesis by choline- and dimethylethanolamine-supplemented cells, respectively. However, most of the newly synthesized IgG1 was not secreted by monomethylethanolamine-supplemented cells, even after 5 h; it remained within the cells. The sensitivity of intracellular IgG1 to endoglycosidase H was examined for probing the movement of IgG1 from the rough endoplasmic reticulum to the Golgi complex. Half of the newly synthesized IgG1 acquired resistance to endoglycosidase H after 30-45 min, 1-1.5 h and 2-3 h in choline-, dimethylethanolamine- and monomethylethanolamine-supplemented cells, respectively. Thus, the transport of IgG1 was markedly retarded by the modification with choline analogues, dimethylethanolamine or monomethylethanolamine, at least in the following two processes, from the rough endoplasmic reticulum to the Golgi complex and from the Golgi to the outside of cells. Modification with monomethylethanolamine was more effective than that with dimethylethanolamine in slowing down the transport of IgG1 and appeared to cause accumulation of IgG1 within the cells. A morphological study was also carried out for the three kinds of cell. The roles of phospholipids in the processes of membrane flow are discussed.

Biopsy of the breast

A study on surgical biopsy for treatment of breast cancer was done by sending out questionnaires to membership institutions of the Japan Mammary Cancer Society. The problems related to diagnostic biopsy of the breast mainly concern the following two points; the first is the methodology, incisional or excisional, the second, whether delay between biopsy and radical mastectomy influences survival. The prognostic features in patients with excisional biopsy were significantly superior. The prognostic features in patients with excisional biopsy were significantly superior. As for the lapse of time between biopsy and radical mastectomy, 14 days were considered safe, and under conditions such as T2 or n0, this maximum was 7 days.

Proton nuclear magnetic resonance study on the roles of histidine residues in the binding of polypeptide chain elongation factor Tu from Thermus thermophilus with aminoacyl transfer ribonucleic acid and guanine nucleotides

Proton nuclear magnetic resonance (1H NMR) spectra were measured of the polypeptide chain elongation factor Tu (EF-Tu) from an extreme thermophile, Thermus thermophilus HB8 [Nakano, A., Miyazawa, T., Nakamura, S., & Kaziro, Y. (1979) Arch. Biochem. Biophys. 196, 233-238], in order to elucidate the environment around functionally important histidine residues. In the present study, the behavior of five histidine C2 proton signals was studied in more detail. A hydrogen-deuterium exchange experiment was carried out on the histidine C2 protons of free EF-Tu, and the previous assignments of C2 proton signals were revised in part. An analysis of the 1H NMR spectra of EF-Tu photooxidized under various conditions indicates that a histidine residue is located in the aminoacyl-tRNA binding site and is probably essential for the binding with aminoacyl-tRNA. A solvent-accessible histidine residue is found to lie near the aminoacyl-tRNA binding site. Furthermore, the effect of paramagnetic hexacyanochromate(III) ion on the 1H NMR spectra of free EF-Tu suggests that another histidine residue lies near the guanine nucleotide binding site.

Nuclear magnetic relaxation study on the interaction of glycyl-L-tyrosine with manganese-carboxypeptidase A in solution

The spin-lattice and spin-spin relaxation rates were measured of the Gly C alpha and Tyr aryl protons of glycyl-L-tyrosine (Gly-Tyr) bound to manganese(II)-substituted carboxypeptidase A (MnCPA) in aqueous solution. The temperature and frequency dependences of the relaxation rates were analyzed using the Solomon-Bloembergen-Morgan equations. The binding modes of MnCPA with Gly-Tyr in solution are different from that of ZnCPA in crystals. 1. Mn(II)-coordinated water of MnCPA is not excluded by the binding of Gly-Tyr substrate molecules. 2. The Gly carbonyl group does not coordinate tightly to the metal ion of MnCPA. The Gly C alpha protons of Gly-Tyr in the productive binding site are appreciably mobile. 3. A non-productive loose binding of another Gly-Tyr molecule is suggested by simulation of the temperature and frequency dependences of the proton relaxation rates.

Combined treatment with by-pass operation, irradiation and immunochemotherapy for advanced thoracic esophageal cancer

Based on the experimental results that operative stress of thoracotomy or laparothoracotomy has enhanced tumor growth remarkably in rats compared with laparotomy, a new combined treatment with by-pass operation, irradiation and immunochemotherapy was investigated in 39 advanced thoracic esophageal cancer patients. At by-pass operation, abdominal esophagus was divided and its proximal stump was closed immediately. Cervical esophagus was then divided and its distal stump was pulled out to the right supraclavicular region to make outer fistula. Thus, anticancer drug was poured into the esophagus through outer fistula very easily just before irradiation and then irradiation was performed under the condition that the lesion was immersed in the drugs. As anticancer agent, Mitomycin-C, 5-Fluorouracil or Bleomycin was given alternately. Lately, the combination of 5-Fluorouracil and Vitamin A was preferably used. The changes of immunological parameters and the survival after the onset of treatment was reported.

Post-operative long-term adjuvant immunochemotherapy with mitomycin-C, PSK and FT-207 in gastric cancer patients

Long-term adjuvant immunochemotherapy carried out on the gastrectomized patients with stomach cancer was reported. The protocol comprises the administration of large-dose of Mitomycin-C (20+10) mg just after gastrectomy and the long-term administration of PSK, FT-207 or (PSK+FT-207). Almost no side effects were observed. According to the studies on the immunological parameters, the increased reactions in PPD skin test and lymphocyte blastogenesis induced by PHA and PWM were observed remarkably in group (P+F) 3 or 6 months after gastrectomy. As for the survival rate, group (P+F) showed the most preferable results at one year in stage IV, at two years in stage III and at three years in all the stages, respectively after gastrectomy.

Lymphocyte responsiveness to phytohemagglutinin and its modification by serum inhibitor in breast cancer patients

Lymphocyte responsiveness in stimulation with phytohemagglutinin (PHA) and the inhibitory effect of autologous serum on lymphocyte responsiveness were investigated in 55 patients with breast cancer. Lymphocytes from patients, even in the late stage of the disease, as well as from normal healthy control, showed an ability to respond to the stimulation with PHA in the presence of pooled normal serum, while lymphocyte responsiveness in the presence of autologous serum was markedly reduced in stage III and IV patients. Similar result was found in the examination of lymphocyte responsiveness with relation to tumor size, where lymphocytes from patients with a large tumor of more than 5 cm in diameter were less responsive when cultured with autologous serum. From these results, it is reasonable to conclude that in patients with breast cancer, the apparent reduction of lymphocyte reactivity may be due to serum inhibitor that may adhere to the lymphocytes, rather than a primary lymphocyte impairment.