Evaluation of mass screening program for stomach cancer

Particular method and program of mass survey examination of gastric cancer were introduced into Miyagi Prefecture and the results accumulated during the past 14 years are presented. During this period, 1,427 cases of gastric cancer (0.18%), as well as many cases of other diseases of the stomach and duodenum, were found by the mass survey. 450 cases were those of early cancer in which invasion of carcinoma was limited to the mucosa and submucosa. The ratio of surgically confirmed early cancer cases to all the stomach cancer cases was 36.4%. Almost in all cases of early stomach cancer there were neither complaints nor clinical symptoms; that is, they were the cases of so-called preclinical cancer of the stomach. The prognosis after surgery of early stomach cancer was remarkably favorable with a five-year survival rate over 90% and the death rate due to stomach cancer was actually decreased in the surveyed population.

Histo-clinical classification and follow-up study of gastric polyp

Gastric polyp was found in 1,616 cases or 0.23% of 711,455 persons through the gastric mass-survey. They were classified into 3 groups: hyperplastic polyp in 61%, gastric polyposa in 34%, and polyp composed of metaplastic epithelium with marked atypism (ATP) in 5%. Gastritis polyposa was subclassified into 5 groups according to its histo-clinical features. Malignant degeneration was suspected in 5 or 2.1% of 236 hyperplastic polyps operated, while no polyp which had changed into cancer was experienced among 974 polyps followed-up by biopsy during the time course of 6 months to 11 years at the longest. On the other hand, coexistence of gastric cancer was found in 13% of cases with ATP. In polyps composed of metaplastic epithelium, there are two kinds of polyp: metaplastic polyp in hyperplastic proliferation and neoplastic polyp. In the follow-up study of 1,104 polyps, the growth of polyp was seen in only 14, and 12 of which were hyperplastic polyp. No change from gastritis polyposa to hyperplastic polyp was observed. The increase in size in 14 polyps was seen mostly 3 to 4 years after they were found and was always transient. From these results, it is considered that most of gastric polyps clinically detected have already completed their growth.

Preventive effect of hapten-reactive thymus-derived helper lymphocytes on the tolerance induction in hapten-specific precursors of antibody-forming cells

The role(s) of helper T lymphocytes in preventing or altering tolerance induction in DNP-specific B lymphocytes was studied. As DNP-reactive helper T cells were reactive against the DNP-portion of the DNP-D-GL molecule, we could probe definitively the physiological role of helper T cells in preventing tolerance induction in B lymphocytes by DNP-D-GL. The results demonstrated that the induction of DNP-specific B cell tolerance by DNP-D-GL can be completely prevented by the presence of DNP-reactive helper T cells, and provide evidence that one critical role of helper T cell participation in humoral responses to antigens is to circumvent the development of a tolerogenic signal that, in the absence of such T cell function, might otherwise ensue after binding of the antigenic determinants by specific B lymphocytes.

The mechanism of tolerance induction in thymus-derived lymphocytes; I. intracellular inactivation of hapten-reactive helper T lymphocytes by hapten-nonimmunogenic copolymer of D-amino acids

Treatment of a p-azobenzoate (PAB) derivative of a copolymer of D-glutamic acid and D-lysine (D-GL) induced a profound state of unresponsiveness to PAB-reactive helper T lymphocytes generated in PAB-mouse gamma globulin (MGG)-primed mice. This unresponsiveness in T lymphocytes was specific for PAB-reactive cells, since the bacterial alpha-amylase-, keyhole limpet hemocyanin-, or ovalbumin-primed helper T lymphocytes were not suppressed by PAB-D-GL treatment. Taking advantage of the relative ease with which PAB-D-GL can induce specific unresponsiveness to helper T lymphocytes in an animal previously primed with PAB-MGG, it was possible to approach certain questions concerning the mechanisms of tolerance-induction and the fate of tolerant helper T lymphocytes in the PAB-D-GL model by utilizing a classical adoptive cell transfer systemmelimination of the possibility of carry-over of the tolerogen with cells or of the generation of suppressor cells as the result of PAB-D-GL treatment as an explanation of the suppression of helper T-cell activity strongly inplicates the existence of a central intracellular mechanism of specific tolerance on the helper T-cell level. The possibility that suppression of the activity of PAB-reactive helper T lymphocytes by PAB-D-GL reflects simple blocking of surface receptor molecules on T lymphocytes was ruled out as it was found that the helper activity of PAB-reactive cells was minimally suppressed even when PAB-D-GL was directly exposed in vitro to helper T lymphocytesmmoreover, the most conclusive evidence on te the tolerant state induced by in vivo exposure of primed T cells to PAB-D-GL. It appears, therefore, that specific tolerance induced by PAB-D-GL' TO PAB-reactive helper T lymphocytes is an example of irreversible inhibition of T-cell reactivity to antigen, reflecting yet to be determined events at the intra- and subcellular levels.

Pseudocyst of the pericardium developing during maintenance hemodialysis. Report of two cases

Two cases of pericardial pseudocyst which developed in the course of maintenance hemodialysis are reported. Both patients were usually free of complaints, although there was evidence of the previous pericarditis with recent accumulation of pericardial effusion. As a possible mechanism leading to pericardial pseudocyst formation, distension of a weak area of the thickened pericardium due to an increase in intrapericardial pressure was assumed. Therefore, pericardial pseudocyst is one of the likely complications of patients on maintenance hemodialysis.

Enhancing activity of synthetic polynucleotides on the induction of anti-hapten antibody response

The enhancing activity of synthetic polynucleotides on the secondary anti-hapten antibody response was studied by using an adoptive transfer system of hapten-primed cells in mice. Hapten-primed B cells were effectively stimulated to produce anti-hapten antibody on challenge with hapten—heterologous carrier in the presence of an appropriate dose of polynucleotides. The enhancing activity of polynucleotides was most effective when administered at the same time as the second antigen and the activity was consistently observed either when these agents were administered in vivo or when hapten-primed cells were treated in vitro with the second antigen and these agents. Polynucleotides enhanced mainly the development of 7S plaque-forming cells (PFC) rather than 19S PFC. The enhancing effect of polynucleotides was not observed in hapten-primed cells from ATS-treated mice, but it was restored by the addition of non-primed lymph node cells or thymus-derived spleen cells from lethally irradiated mice reconstituted with thymocytes.

These results clearly indicate that polynucleotides enhance the anti-hapten antibody response of hapten-primed B cells to the hapten—heterologous carrier through activation of non-primed T cells specific for the heterologous carrier and do not directly affect hapten-primed B cells. The mechanism of the stimulation of T cells by polynucleotides is discussed.

Suppression and enhancement of allografted tumour

Passively administered alloantiserum suppressed the in vivo growth of allografted mouse plasmacytoma X5563 with the aid of host cells, probably macrophages, but not with complement. Furthermore, it was shown that alloantiserum probably participates in the process of tumour cell destruction in vivo as opsonin rather than as cytophilic antibody. On the other hand, administration of a decreased dose of the same whole antiserum or its fractions of γM as well as γG, or prior active immunization with living tumour cells, could induce the characteristic pattern of immunological enhancement. From concurrent studies, it was considered that enhancement might have been induced by the suppression of the development of the host's own immunity against tumour.

Antibody production in mice. VI. Effect of anti-carrier antibody on cellular co-operation in the primary anti-hapten antibody response

We studied the effect of passively administered anti-carrier and anti-hapten antibodies on the primary anti-hapten antibody response to hapten—carrier conjugates in mice. Bacterial α-amylase (BαA), Taka-amylase A (TAA) and keyhole limpet haemocyanin (KLH) were used as carrier molecules, and 2,4-dinitrophenyl (DNP) group was used as a haptenic determinant.

Three groups of mice were injected intravenously with anti-carrier antiserum, anti-hapten antiserum and normal serum as the control, respectively, immediately after the immunization with the hapten—carrier conjugate.

The primary anti-carrier antibody response was markedly suppressed by the passively administered anti-carrier antibody but not anti-hapten antibody. However, the primary anti-hapten antibody response was suppressed not only by passively administered anti-hapten antibody but also by the injection of anti-carrier antibody in an early period after the immunization.

When anti-carrier antibody was given twice 0 and 7 days after immunization, the primary anti-hapten antibody response was markedly suppressed and the suppressive effect was observed even at a later period. In contrast, anti-hapten antibody given by the same schedule as above suppressed only the primary anti-hapten antibody response, but not the anti-carrier antibody response.

Passively administered anti-carrier antibody did not suppress carrier-specific helper cell development, but still suppressed the development of B memory cells and antibody formation against carrier determinants. The antigen dose required for the development of B-cell memory was much higher than that necessary for the stimulation of T cells.

Passively administered anti-carrier antibody clearly inhibited the cellular cooperation between carrier-committed helper cells and hapten-specific B cells and the augmented primary anti-hapten antibody response induced by carrier-primed T cells was clearly abolished. Furthermore, mice preimmunized with carrier showed significantly lower anti-hapten antibody response following the hapten—carrier challenge. Moreover, development of hapten-specific memory cells was also suppressed.

Thus, even in the non-specific antibody-induced suppression by anti-carrier antibody, negative feedback effect of a B-cell product with anti-carrier specificity exclusively regulates the B-cell line development and differentiation.

Antibody production in mice. V. The suppressive effect of anti-carrier antibodies on cellular cooperation in the induction of secondary anti-hapten antibody responses

Cooperative induction of secondary anti-hapten antibody responses was studied by using non-cross-reactive carrier proteins, bacterial α-amylase (BαA), Taka-amylase A (TAA) and keyhole-limpet haemocyanin (KLH), and the 2,4-dinitrophenyl (DNP) and benzylpenicilloyl (BPO) groups as haptenic determinants.

Lymphoid cells obtained from mice primed with a hapten-carrier conjugate could be effectively stimulated with a hapten-heterologous carrier conjugate, provided that lymphoid cells primed to the heterologous carrier were also present. In the carrier-primed lymphoid cell population, helper activity of thymus-derived cells developed earlier following carrier immunization than did the capacity of antibody-forming cell precursors (AFCP) to produce an effective anti-carrier antibody response upon secondary stimulation. Attempts to generate hapten-specific helper cell activity were unsuccessful. Thus, cells primed to one haptenic determinant failed to exert a helper function with cells primed to a second hapten upon subsequent administration to the two haptens together on the same heterologous carrier molecule.

In order to distinguish among carrier determinant specificities which react with thymus-derived helper cells from those which react with bone marrow-derived AFCP, the capacity of various anti-carrier antibodies or antibody fragments to suppress either anti-carrier antibody production alone or together with helper cell function in adoptive secondary anti-hapten antibody responses was tested. In this system, it was found that 7S anti-carrier antibody suppressed the reaction of helper cells and carrier-specific AFCP such that both the anti-hapten and anti-carrier antibody responses were abrogated. By contrast, passively administered 3.5S fragments of anti-carrier antibodies selectively prevented the stimulation of carrier-specific AFCP to produce anti-carrier antibodies, but had no effect on the capacity of carrier-specific helper cells to facilitate the secondary anti-hapten antibody response. As expected, passively administered 7S anti-hapten antibodies selectively abrogated the production of anti-hapten, but not anti-carrier antibodies. These data are discussed in the context of suggesting that distinct determinant sites on carrier molecules are recognized independently by thymus-derived helper cells and by bone marrow-derived AFCP.