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Biomedical subjects

T Tokunaga

Publications and source records attributed to T Tokunaga.

At least 307 records · Page 17Linked to original sources
PubMed1980

Total synthesis of tRNAfMet.

Oligonucleotides corresponding to the E. coli tRNAfMet fragments and their analogs have been synthesized by the phosphodiester or phosphotriester method. The nascent fragments were joined by using RNA ligase to yield a total tRNA molecule. The synthetic molecule was tested its ability to accept methionine in the presence of purified methionyl-tRNA synthetase from E. coli. The charged tRNA and the hydrolyzed methionine were isolated by gel filtration. The discharged tRNA was characterized by nearest neighbor analysis and 5'-end analysis.

Base Sequence↗
PubMed1979

Delayed-type hypersensitivity (DTH) in BCG-sensitized mice I. Lack of suppressor T cell activity on DTH to sheep red blood cells.

Mice pretreated with an intravenous (i.v.) injection of BCG (BCG-sensitized mice) and then immunized intravenously with a high dose (10(8)--10(9)) of sheep red blood cells (SRBC) 2 weeks later developed strong delayed-type hypersensitivity (DTH) to SRBC, as in mice pretreated with cyclophosphamide (CY) (CY-treated mice) and then immunized with SRBC 2 days later; normal mice given the same dose of SRBC did not show such DTH. The mechanism of this strong DTH to SRBC which developed in BCG-sensitized mice was studied, by comparing it with that in CY-treated mice. The transfer of either whole spleen cells or thymus cells, but not serum, obtained from mice immunized with i.v. injections of 10(9) SRBC 4 days previously (hyperimmune mice) did not suppress either the induction or the expression of DTH to SRBC in BCG-sensitized mice, but suppressed those in CY-treated mice. The suppressor cells were SRBC-specific T cells. Adoptive transfer of DTH to SRBC by spleen cells from either BCG-sensitized mice of CY-treated mice to hyperimmune recipients failed. The adoptive transfer of DTH from BCG-sensitized mice to normal recipients also failed if the spleen cells from hyperimmune mice were cotransferred. Whole body irradiation (600 rad) of mice 2 hr before or after the time of immunization with SRBC reduced significantly DTH to SRBC in both BCG-sensitized and CY-treated mice. It was noticed that the total number of spleen cells in BCG-sensitized mice was 3--4 times larger than that in CY-treated mice. From these results, we conclude that the entity of effector T cells of DTH to SRBC induced in BCG-sensitized mice and in CY-treated mice was not different in terms of susceptibility to suppressor T cells and irradiation, but that the total numbers of effector T cells generated in these mice differed remarkably, resulting in the above-described different responsiveness to suppressor T cells transferred passively.

Animals↗
PubMed1979

Immunotherapeutic trials of murine and guinea-pig solid tumors by oral administration of BCG.

Efficacy of oral administration of BCG on the growth of various tumors in mice and guinea pigs was studied. The growth-inhibitory effect varied depending on the tumor systems and the experimental conditions. Weekly oral administrations with 5-mg doses of BCG to mice or 80-mg doses of BCG to guinea pigs were ineffective on syngeneic mouse melanoma B16 or syngeneic guinea pig hepatocarcinoma line-10 but effective on syngeneic mouse carcinoma IMC and syngeneic guinea-pig fibrosarcoma H9A. Oral BCG seemed effective also on allogeneic mouse carcinoma Ehrlich, developed with a relatively small size of tumor cell inoculum, and on guinea-pig syngeneic liposarcoma H10. On Ehrlich tumors, oral BCG given once a week seemed to have better effects than did oral BCG given twice a week or subcutaneously once or repeatedly; heat-killed BCG given orally showed no effect. However, it seems premature to draw a definite conclusion on the efficacy of oral BCG on Ehrlich and H10 tumors, because some of these tumors regressed spontaneously even in nontreated control animals. The host responses to oral BCG were studied with the following results. Weekly oral administration with 80-mg doses of BCG to guinea pigs elicited positive skin reactions to 25 TU PPD in about 65 days after the first BCG, while a single sc injection of 8 mg of BCG did so within 10 days. Orally administered BCG organisms were recovered largely from Peyer's patches, a little from the mesenteric lymph nodes, and very little from the liver and the spleen. The BCG distributive pattern was in reverse order when BCG was given subcutaneously. Histologic examinations of Peyer's patches indicated enlargement of germinal centers, in which primitive reticular cells proliferated prominently and the macrophages with tingible bodies scattered frequently.

Administration, Oral↗
PubMed1978

In vitro cytotoxicity of peritoneal macrophages activated with Mycobacterium smegmatis.

Incorporation of 3H-TdR into EL4 leukemic cells in vitro was inhibited by peritoneal exudate cells (PEC) harvested from syngeneic C57BL/6J mice given an intraperitoneal (i.p.) injection of 1x10(7) viable Mycobacterium smegmatis ATCC 607 (Smeg) 4 days before. This phenomenon was also observed in the following five systems of PEC from animals and syngeneic tumor cells: C57BL/6J mice and B16 melanoma; DBA/2 mice and P815 mastocytoma; SWM/Ms mice and K5 fibrosarcoma; BALB/c, nu/nu mice and KKN-1 fibrosarcoma; and strain 2 guinea pigs and line-10 hepatoma. The in vitro cytotoxicity of the PEC activated by viable Smeg was much higher than those activated by dead-Smeg, viable BCG or proteose peptone. The activity of the adherent fraction of the PEC was stronger than that of the nonadherent one, and not influenced by either anti-theta or anti-mouse lymphocyte rabbit sera. The PEC induced with Smeg 4 days before contained a large population of mononuclear cells (88.9%) and a significant level of polymorphonuclear cells (PMN) (3.2%), and showed a much higher cytotoxicity than the PEC induced with Smeg 3 hr before, which contained a much larger population of PMN (71.9%), suggesting that PMN were not the effector cells in this system. In vitro and in vivo treatment with macrophage-inhibitors such as carrageenan, trypan blue and cytochalacin B, reduced the activity of the PEC. All of these facts suggested macrophages as the effector. Viable macrophages were required for the growth inhibition of EL4 in vitro: gamma-ray irradiated or freeze-thawed macrophages were ineffective. Kinetic studies revealed that inhibition of 3H-TdR incorporation into EL4 cells started within 3 hr of incubation together with the activated macrophages at an effector to target (E/T) ratio of 5, and the incorporation decreased gradually with the lapse of incubation time. On the other hand, 51Cr release from labelled EL4 was undetected when the E/T ratio was 5 but detected at on E/T of 10 or more. Even at the higher E/T ratio, at least 10 hr were needed until the release of 51Cr, suggesting that the activated macrophages produced growth inhibition of tumor cells followed by cell destruction.

Animals↗
PubMed1978

Strain difference of delayed-type hypersensitivity to BCG and its genetic control in mice.

Delayed-type hypersensitivity to BCG was remarkably different in two inbred strains of mice, SWM/Ms and C3H/He, when measured by the spleen index, the disappearance of peritoneal macrophage, or the footpad reaction. High responsiveness in the SWM/Ms strain appeared to be dominant over low responsiveness in the C3H/He strain. Results of the footpad reaction test if F1, F2, and backcross hybrids of these two strains of mice suggested that the delayed-type hypersensitivity was mainly controlled by a gene which was transmitted under Mendel's laws and was possibly non-H-2 linked. The spleen cells and their nylon wool nonadherent fraction from BCG-infected C3H/He mice were not reactive to purified protein derivative in vitro, whereas both the spleen cells and the nylon wool nonadherent fraction from BCG-infected SWM/Ms mice reacted well to purified protein derivative. Possible mechanisms of the different responses in the delayed-type hypersensitivity to BCG were discussed.

Animals↗
PubMed1978

Mouse-strain difference in immunoprophylactic and immunotherapeutic effects of BCG on carcinogen-induced autochthonous tumors.

The prophylactic and therapeutic effects of BCG on the tumors induced by 3-methylcholanthrene (MCA) were studied comparatively between two inbred mouse strains, SWM/Ms and C3H/He, the first tumor appeared 5 weeks after MCA and the cumulative tumor incidence reached almost 100% within 20 weeks. On the other hand, the first tumor appeared 8 weeks after MCA in SWM/Ms, the number of tumor-bearers increased more slowly than in C3H/He, and the final tumor incidence (at 30 weeks) was about 90-80%. Single subcutaneous injection with BCG 2 weeks prior to MCA significantly protected SWM/Ms from tumor development, but not in C3H/He. These tumors, once appeared grew progressively and killed the hosts equally in both the strains. Intratumor (i.t.) injection with BCG showed more or less therapeutic effects in SWM/Ms; most tumors regressed or retarded after BCG. The time period after tumor-appearance to tumor-death was prolonged in most of SWM/Ms mice given i.t. injection with BCG, except a few mice that died earlier than non-treated controls after BCG. Contrary, no therapeutic effect of i.t. injection with BCG was observed in C3H/He. different host responses to BCG between SWM/Ms and C3H/He were found by the peritoneal macrophage disappearance test and the footpad reaction test; SWM/Ms was a high-responder to BCG and C3H/He was a low-responder. The marked differences between SWM/Ms and C3H/He in prophylactic and therapeutic effects of BCG on the autochthonous tumors were discussed in terms of difference of the host immune response to BCG that is defined genetically.

Animals↗
PubMed1978

Tumor-specific skin-reactive antigen solubilized from a syngeneic guinea pig liposarcoma by 3M potassium chloride.

Tumor-specific and skin-reactive antigen of a syngeneic liposarcoma (H-10) of Hartley/F guinea pig was solubilized with 3M potassium chloride and purified by precipitation with 2M ammonium sulfate, followed by Sephadex G-200 gel filtration. The antigenic activity of 7 fractions obtained was estimated by the delayed-type skin reaction elicited in syngeneic animals immunized with H-10 cells admixed with BCG. Accurate relative activity of the fractions comparable to the skin reaction elicited by living H-10 cells was calculated by the parallel line assay method in which the dose-response curves of the fractions are compared with that of living cells. About 30 approximately 50 microgram protein of the 3 fractions eluted slowly from the Sephadex column elicited the skin reaction equivalent to that elicited with 1 X 10(6) of living H-10 cells. Tumor-specific skin reactivity per microgram protein of these 3 fractions was roughly 20 approximately 40 times higher than that of lyophilized cells.

Animals↗
PubMed1977

Responses of tumors induced in inbred guinea pig strain JY=1 and strain Hartley/F to BCG.

A transplantable fibrosarcoma induced in inbred JY-1 guinea pig strain by 3-methylcholanthrene (MCA) and designated J4, an allotransplantable subline of J4 (JH4) which was obtained by the transplantation of J4 into the inbred Hartley/F guinea pig strain and maintained by passages in this strain, and a syngeneic liposarcoma H10 induced in a Hartley/F guinea pig by MCA were tested for their immunotherapeutic response with BCG. The growth of J4 and H10 tumors was suppressed in most of the animals when tumor cells were mixed with BCG before being injected sc into BCG-immune or BCG-nonimmune recipients. The growth of the JH4 tumor was suppressed at the sites of injection with a mixture of tumor cells and BCG in BCG-immune recipients but not in nonimmune animals. All guinea pigs surviving the injection of a tumor cell-BCG mixture resisted a second tumor cell challenge. When subcutaneous sarcomas grew to about 8-15 mm in diameter, BCG was injected into the tumors. The growth of JH4 tumor was not influenced by the injection in either BCG-immune or BCG-nonimmune animals, while the regression of the established J4 transplants was produced in 2 of 3 nonimmune recipients. The growth of the H10 tumor was not inhibited with an intratumor injection into nonimmune guinea pigs, while the H10 tumor regressed in BCG-immune animals for 4-5 weeks after intratumor injection and thereafter grew progressively. Skin reactions in animals that received repeated intradermal injections of the tumor cells and BCG were tested with 10(6) viable tumor cells as eliciting antigens. Typical delayed-type hypersensitivity reactions that were specific to the homologous antigens were observed. The possible reasons for the different responses to BCG among the guinea pig tumors, including line-10 hepatocarcinoma in strain-2 guinea pigs, were discussed.

Animals↗
PubMed1976

Multiple mating types of Mycobacterium smegmatis.

Multiple mating systems were found in the strains of Mycobacterium smegmatis. Nineteen wild type strains were classified into five different groups according to their mating behavior. All crosses between substrains derived from the same wild type strain or between substrains belonging to the same group were infertile, while eight different intergroup crosses were fertile. It was suggested that in most of the fertile crosses, chromosome transfer was unidirectional. Genes controlling matings were resistant to curing by acridine dye, sodium dodecyl sulfate and higher temperature suggesting that they were chromosomal genes. However, the location of these genes could not be demonstrated because none of the chromosomal markers tested was found to be linked to these mating genes.

Acriflavine↗