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Biomedical subjects

T Iwaguchi

Publications and source records attributed to T Iwaguchi.

At least 55 records · Page 3Linked to original sources
PubMed1985

Cytolytic activity of cytotoxin isolated from Indian cobra venom against experimental tumor cells.

Cytolytic activity of cytotoxin isolated from the venom of the Indian cobra (Naja naja) on experimental tumor cells was far stronger than that on normal cells such as peritoneal exudate cells, spleen cells, and erythrocytes of the rat. The effect on Yoshida sarcoma cells was temperature-dependent, being stronger at 37 degrees C than at 0 degrees C. Intramolecular disulfide linkages and free amino groups in the cytotoxin molecule were shown to be essential for the lytic action on the cell membrane. Yoshida sarcoma cells treated with 0.1 mM N-ethylmaleimide reduced the cytolytic action of the toxin. Antitumor activity of the cytotoxin toward a Yoshida sarcoma inoculated intraperitoneally into a rat was not observed.

Animals↗
PubMed1984

Evaluation of PSK, an antitumor protein-bound polysaccharides, by thymocyte electrophoresis.

It was clear that the proportion of high mobility cells in thymus tended to increase during tumor development by cell electrophoresis. Although the antitumor activity of PSK, protein-bound polysaccharide or mitomycin-C was similarly effective in sarcoma-180-bearing mice, the histogram pattern of thymocyte electrophoresis differed markedly from each other. Normally, the proportion of high mobility cells of thymocyte increased more with the administration of mitomycin-C than that of the untreated tumor-bearers, while PSK kept the thymic cell mobility histogram normal. Changes of thymocyte electrophoresis caused by the drugs also correlated with the depression of their antiinfectious activity. Using the fully automated cell electrophoretic instrument, the drug can be evaluated simply from the viewpoint of antiinfectious efficacy.

Animals↗
PubMed1984

Host-mediated inhibition of rat bladder cancer growth by cyclophosphamide and purine salvage pathway-related enzyme activity of lymphocytes.

In ACI/N rats pretreated with cyclophosphamide (CY) growth of the bladder cancer, BC-47, and adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in lymphocytes were investigated to clarify the possible antitumor effect via the immune system of the chemotherapeutic agent. A single dose of 50 mg/kg of CY with the tumor implantation 3 days later gave rise to tumor regression following temporary progression around day 15 and significant increase of peripheral lymphocytes with higher PNP activity on days 7 to 10 of the tumor implantation. In the thymus such lymphocytes increased 3 days earlier. The antitumor effect was not demonstrated in athymic nude mice. In the light of the results and elimination of suppressor T precursors by CY, it was postulated that T lymphocytes with higher PNP activity act as effector cells in the antitumor immunity whereas suppressor T precursors belong to the cell population with lower PNP activity.

Adenosine Deaminase↗
PubMed1984

Analysis of electrophoretic mobility histogram of mouse thymocytes during tumour development.

The population of medullary thymocytes without peanut agglutinin (PNA) receptor consisted of two groups: Lyt-1+ .2- cells with a high mobility of 1.0 micrometer/sec/V/cm, and Lyt-1+ .2+ cells with a low mobility of 0.7 micrometer/sec/V/cm. Also used were cortical thymocytes with PNA receptor: these were Lyt-1+ .2+ cells, having low mobility. In C3H/He mice bearing plasmacytoma X5563, a low mobility peak appeared in the histograms of peripheral lymphocytes. In contrast, a high mobility peak appeared in the histograms of thymocytes. Using full automated analytical instrumentation, it was determined that the appearance of high mobility cells during tumour growth strongly correlated with the decreased proportion of low mobility cells in thymus.

Animals↗
PubMed1983

Emergence of low-mobility T lymphocytes in cancer patients and its clinical significance.

Electrophoretic mobility of lymphocytes from healthy individuals and cancer patients was analyzed by means of a fully automated cell electrophoresis apparatus (Parmoquant). Electrophoretic mobility histograms showing two distinct peaks were obtained with peripheral blood lymphocytes from normal subjects. A border line was placed at the mobility of 0.95 microns/sec/V/cm, and cells slower than this were designated as low-mobility cells (LMC) and faster cells as high-mobility cells (HMC). LMC, constituting the slower peak, consisted mainly of B cells and a small number of T cells (LMT). HMC, the constituent of the faster peak consisted of two types of T cells (HMT). In patients with malignant tumors, analysis revealed lowered electrophoretic mobility of T cells, with T/B ratios comparable to those in normal subjects. An increase in the percentage of LMT seemed characteristic of suppressed immunity in cancer patients since it showed a strongly positive correlation with the percentage population of IgG . FcR-positive T lymphocytes and with the serum level of immunosuppressive substance. The incidence of abnormal LMT/HMT ratios was highest in patients with recurrent cancer, and it was also high in the advanced stages of gastrointestinal cancer. This index could provide useful information for the early detection of cancer relapse during postoperative follow-up. A fully automated electrophoresis apparatus greatly facilitated the measurement (5 min/100 cells) and permitted quantitative and statistical analysis of mobility histograms of cell electrophoresis.

Ascitic Fluid↗
PubMed1983

Mechanism of the antitumor activity of 5,5'-bis(2'-tetrahydropyranyl) secalonic acid D against Meth-A.

The mechanism of the antitumor activity of 5,5'-bis(2'-tetrahydropyranyl) secalonic acid D (PSA) was examined in Balb/c mice bearing Meth-A fibrosarcoma. IP-injected PSA showed remarkable antitumor activity against IP-implanted Meth-A tumor. Antitumor activity of PSA was not abolished by treatment with silica as an antimacrophage agent or anti-asialo GM1 antiserum that selectively eliminates natural killer cells. Although it was significantly suppressed by treatment with antithymocyte globulin in Balb/c mice, PSA was effective against Meth-A tumors implanted in athymic Balb/c mice. PSA inhibited in vitro Meth-A proliferation as effectively as mitomycin C and was not effective against Meth-A tumor implanted SC at a site where direct contact of PSA and Meth-A cells was unlikely. These results suggest that the antitumor activity of PSA was mainly achieved by inhibiting Meth-A cell proliferation, although the host T cell-mediated immunity was partly involved in the eventual therapeutic efficacy of PSA.

Animals↗
PubMed1983

[Analysis of electrophoretic mobility pattern of immunocompetent cells in the tumor-bearing host].

Effect of tumor burden on the electrophoresis of lymphocytes and macrophages was analyzed with a fully automated cell electrophoretic instrument (Parmoquant). The histogram patterns of peripheral lymphocytes of mice shifted to the lower mobility zone, and that of thymocytes shifted reversely, in the course of development of tumor. In cancer patients, emergence of low mobility T cell (LMT) was observed, and LMT correlated with immunosuppressive factors significantly. The ratio of LMT to high mobility T cells (HMT) tended to increase with tumor growth, and showed extremely high value in the case of recurrent cancers. In the follow-up studies, the LMT/HMT value varied in parallel with tumor growth. The unimodal patterns of macrophages changed to multiple peaks with tumor burden, in experimental animals and in clinical study. At terminal stage, it showed unimodal peak of lower mobility and phagocytic activity decreased. The result indicates that LMT associated with depressed immune state of cancer patients, and electrophoresis of immuno-competent cells may be usefull for cancer diagnosis and early detection of recurrence, because this method is very easy to assay and highly reproducible.

Animals↗
PubMed1981

Drug sensitivity of rat bladder cancer in syngeneic hosts and athymic nude mice.

The effects of chemotherapeutic agents on BC-47 rat bladder cancer were investigated in nude mice and syngenetic hosts to clarify the influence of host factors on chemotherapy. The BC-47 cancer was rich in stroma and lacked central necrosis in syngeneic ACI/N rats. In contrast, in nude mice it had little stroma and underwent necrosis in the center, and cancer cells proliferated primarily at the periphery in contact with the normal host tissue. The cancer showed similar patterns of sensitivity to bleomycin, 1,3-bis (2-chloroethyl)-1-nitro-sourea, 5-fluorouracil, and mitomycin C in both hosts. In contrast, adriamycin and pyranyl secalonic acid D (pyranyl secalonic acid) had different effects in the two hosts, being significantly effective in rats, but ineffective in nude mice.

Animals↗
PubMed1980

5-Di-(2'-tetrahydropyranyl)secalonic acid D as a new antibiotic derivative with anticancer activity.

A pyranyl derivative was chemically synthesized from secalonic acid D, an antibiotic obtained from culture filtrates of Penicillium oxalium, and its anticancer activity towards a highly antigenic rat bladder cancer, BC-47, implanted into inbred ACI/N rat was studied. The anticancer effect of the drug was similar to that of adriamycin. Delayed initiation of treatment, starting 5 days after the cancer implantation, was more effective than treatment starting from day 1. In addition, it was less effective in an immunodeficient host subsequently implanted with BC-47. This compound is thought to retard the cancer cell growth until the appearance of tumor immunity in the host.

Animals↗
PubMed1978

Anticancer activity of isomers of 6-phenyl-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole.

Three phenylimidazothiazole isomers, L-(-)-form (levamisole), D-(+)-form (dexamisole), and DL-(+/-)-form (tetramisole), modulate mouse and rat immune responsiveness. They depress the relapse of urinary bladder cancer, BC-47, when they are used with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) for treatment of rats bearing BC-47. Levamisole was the most effective isomer. Effectiveness of the isomers is expressed by their ability to enhance the number of plaque-forming cells to sheep red blood cells. They also stimulate the DNA synthesis of murine lymphocytes in vitro.

Animals↗
PubMed1978

Effect of chemotherapeutic agents on the growth of rat bladder cancer, BC-47.

Effect of clinically available chemotherapeutic agents on transplantable and tissue culture bladder carcinoma cell line, BC-47, which were syngeneic to host animals, was confirmed. Adriamycin, vincristine, and bleomycin possessed predominant antitumor activity. 1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) also reduced the tumor load of the host after which the tumor began to grow at the site of inoculation. Alkylating agents such as nitrogen mustard N-oxide (Nitromin), cyclophosphamide, 3,3'-dimesyloxydipropylamine tosylate (864T), and mitomycin-C possessed a weak activity, while antimetabolites such as 5-fluorouracil, 1-(1'=furyl)-5-fluorouracil (FT-207), cytosine arabinoside, and behenoylcytosine arabinoside possessed no activity.

Animals↗
PubMed1976

In vivo and in vitro cell-mediated immune reactions to auto-chthonous tumor extracts in patients with gastric cancer.

Sixty patients with advanced gastric cancer were subjected to the macrophage electrophoretic mobility test and delayed hypersensitivity skin test to tumor and normal tissue (gastric mucosa) extracts. Tumor extract induced significant inhibition of macrophage mobility in 51% and positive skin reaction in 32% of examined cases. Close correlation was observed between macrophage inhibition and diameter of skin reaction to tumor extract. Incidence of positive reaction in both tests to normal tissue extract was 55% and 12%, respectively. Significant inhibition of macrophage to tumor extract was also observed in breast cancer, but not in superficial gastric cancer and healthy persons. Normal tissue extract did not induce significant inhibition of macrophage in gastric ulcer. These results suggest that macrophage electrophoretic mobility test indicates a certain aspect of tumor-associated (but not tumor-specific) immunity in cancer patients. Macrophage inhibition appeared to be related with macroscopic tumor types rather than to clinical stages. Positive skin reaction to tumor extract was observed in Stages II, III, and IV of gastric cancer.

Antigens, Neoplasm↗
PubMed1975

Change in immunosensitivity of Yoshida sarcoma produced by chemical modification of cell-surface membrane.

Change in immunosensitivity of various chemically modified cells to the specific antibody was investigated in the Donryu rat-Yoshida sarcoma system. Among various agents, Amphotericin-B and cetyltrimethylammonium bromide were effective in increasing the immunosensitivity. This effect was not due to the general damage of cell membrane but to the increase of antigen exposed on the cell-surface membrane.

Amphotericin B↗