Evidence for involvement of mast cells in tumor suppression in mice

Mast cell-deficient W/Wv mice had an increased tumor incidence after subcutaneous treatment with 3-methylcholanthrene, compared with that in normal congenic mice treated in the same way. This increased tumor incidence was suppressed to the normal level when the carcinogen was given after the mast cell deficiency had been overcome by transplantation of bone marrow cells from normal congenic mice. The W/Wv mice, however, were not defective in natural killer and T-cell-mediated cytotoxic activities. These results support the hypothesis that mast cells are involved in tumor suppression.

Regulation of primary antibody response in mice by two types of suppressor cells resistant to anti-thy-1 serum treatment

The anti-SRBC antibody response of normal young adult mice (about 3 months old) was specifically suppressed, when the spleen cells derived from the syngeneic donor mice that had been previously primed with a high dose of SRBC were adoptively transferred at the time of antigenic challenge. The suppression was antigen-specific and was mediated by a fraction of the immune spleen cells which appeared to belong to either B cells or their progeny antibody-forming cells. The differences were observed in the properties of the suppressor cells in terms of the period after the priming and the radiosensitivity; i.e., immune spleen cells taken from the mice which had been immunized with SRBC 5 days earlier were able to suppress only 19S PFC, whereas those taken from the mice which had been immunized 14 days earlier were able to suppress both the 19S and 7S PFC responses, and the former cells were susceptible to 400 R X-rays, but not the latter. These two types of suppressor cells appeared to play an important role in the regulation of the sequential change of 19S and 7S antibodies during the primary immune response.

Absence of correlation between T-lymphocyte activity and development of carcinogen-induced skin tumor in mice

Splenic lymphocytes obtained from female ICR/JCL mice, which had received combined radiation and chemical treatment for induction of skin tumors on their back skin, were tested for their ability to undergo proliferative response to non-specific mitogens as well as to allogeneic lymphocytes in vitro during 18 months after carcinogenic treatment. The treated mice, 168 in all, were divided into three groups: (a) 53 mice with no tumor, (b) 30 mice with skin papilloma, and (c) 85 mice with malignant skin tumor. Control mice, 39 in all, received no treatment. The local carcinogenic treatments used in this study induced a relatively long-lasting suppression of T-cell activities as detected by proliferative response to mitogens. Nevertheless, there was no significant difference in T-cell activities among the three groups of mice that developed (a) no tumor, (b) skin papilloma, or (c) malignant skin tumor. The results obtained with proliferative response to allogeneic lymphocytes were essentially similar. A preliminary study on the induction of cytotoxic T cells from splenic lymphocytes against allogeneic target cells in vitro also indicated that mice which developed tumors were not necessarily the ones which manifested reduced cytotoxic T-cell activity. These results suggest that reduced T-cell function was not a direct cause or not even a prerequisite for development of skin tumors in ICR mice.

Partial deletion of chromosome No. 2 in myelocytic leukemias of irradiated C3H/He and RFM mice

Chromosomes of mouse myelocytic leukemias that developed in 7 irradiated mice, 3 C3H/He males, 1 RFM female, and 3 RFM males were analyzed with chromosome-banding techniques. Chromosomes No. 2 were partially deleted in 6 of the 7 mice. Although the deleted No. 2 chromosomes varied in size in the 6 mice, one common characteristic was noted in all these deletions: A segment lying between a certain band in the region 2C and a band in the region 2E, including the whole region 2D, was missing. Another consistent abnormality was an addition or a loss of the Y-chromosomes in the fraction of cells in all 6 males. In addition to these consistent abnormalities, various chromosomes had structural abnormalities. The RFM female, which did not have the abnormal No. 2 chromosome, had abnormalities in chromosomes No. 3, 4, 11, 12 and 15 and in the X-chromosome. Of the 20 chromosome pairs, only such chromosomes as No. 1, 5, 8, 14, 17, and 19 and the Y-chromosome did not have the structural abnormalities. The possible role of the partial deletion of the No. 2 chromosome was considered in relation to the development of mouse myeloid leukemias.

[Quarantine and health control of the squirrel monkey (Saimiri sciureus) (author's transl)]

A total of two hundreds and seventy squirrel monkeys (Saimiri sciureus) of both sexes were imported from South America through an animal dealer of the U. S. A. in eight lots from May, 1973 to July, 1974. They were investigated for the presence of the parasites for a maximum of fifteen months including nine weeks of quarantine period from the time of import. The mortality rate before or immediately after arrival at our laboratory reached 56.7% in the first two lots. This, however, could be reduced later to 4.8% by improving some conditions of transportation. Bacteriological surveys revealed no shigella or salmonella infections during the quarantine period. No tuberculin positive reactors were also detected. Filarial infestations seemed to be common in this species; about 45.5% had adult worms in the peritoneal cavity and about 65% harbored microfilaria in the peripheral blood. Acanthocephla was also found in a high rate in the lower alimentary tracts. It has been suggested that the worms disappear in fifteen months by keeping animals in the intermediate host-free circumstances. The sarcocyst was found in the femoral muscle of 7 (18.9%) of 37 animals examined histologically.

Early decline of thymic effect on T cell differentiation

Thymic lobes of B6C3F1 mice ranging in age from 1 day to 11 weeks were implanted under the kidney capsule of T cell deprived syngeneic young adult TXB mice, and the capacity of the thymus grafts to influence the maturation of T cells was assessed at 6 and 12 weeks after the implantation in terms of (a) regenerative activities of the grafted thymus, (2) splenic T cell dependent anti-SRBC response, and (c) mitogenic reactivity of spleen and lymph node cells to T cell specific mitogens. The results revealed that: (1) thymic tissues from 1 week old donors were most efficient in restoring the immune potential of adult TXB mice; (2) a decline in mitogenic reactivities of spleen and lymph node cells was observed in recipients of thymus grafts from donors of 1 month and older; and a decline of splenic helper T cell function was observed in recipients of thymus grafts from 11 weeks old donors. The significance of this early decline in the thymic effect on T cell differentiation is discussed.

Lack of toxicity of chenodeoxycholic acid in the squirrel monkey

The toxicity of chenodeoxycholic acid was studied in squirrel monkeys of both sexes. The drug was orally administered to five groups of 26 animals each at a daily dose of 0, 10, 20, 40, and 80 mg per kg, respectively, for a maximum of 52 weeks. No clinical symptoms that could suggest drug toxicity were observed. All laboratory studies, including liver function tests, were within normal limits. The proportion of lithocholic acid in biliary acids remained unchanged, whereas that of chenodeoxycholic acid was dose-dependently increased. No histopathological changes considered to be attributable to drug administration were observed.

Absorption, excretion and metabolism of a new dihydropyridine diester cerebral vasodilator in rats and dogs

1. After oral administration of [14C]dihydropyridine diester, the plasma concn. of radioactivity was similar in rats and dogs, reaching a maximum at 0-5 to 1 h and decreasing with a half life of about 3-5 h. The plasma concn. of unmetabolized drug in dogs was 10 times higher than in rats. Radioactivity in rat tissue was high in liver, kidney and lung after both oral and intravenous administration. 2. In both species, 66-72% of radioactivity was excreted in faeces and 23-29% in urine in 48 h, regardless of the route of administration. Biliary excretion in rats after oral dosage amounted to 65%. 3. Eight metabolites were identified from urine of dogs and rats. They were derived from one or several of the following pathways: I, debenzylation of the N-benzyl-N-methylaminoethyl side chain; II, reduction of the 3-nitro group on the phenyl substituent; III, oxidation of the 1,4-dihydropyridine ring to the corresponding pyridine; IV, oxidative removal of the N-benzyl-N-methylamino group yielding a carboxylic acid; V, hydrolysis of the N-benzyl-N-methylamino-ethyl ester to the corresponding carboxylic acid; VI, hydroxylation of the 2-methyl group of the 1,4-dihydropyridine ring to hydroxymethyl.

Histocompatibility and T-B cell cooperation in mouse radiation chimeras

Cooperative interaction between histocompatible as well as histoincompatible T and B cells in vivo was studied with B cell-bearing syngeneic radiation chimeras receiving syngeneic, semiallogeneic, or allogeneic A and T cells in various combinations. The results indicated the following: i) Histoincompatible T and B cells normally did not cooperate successfully for generation of antibody-forming cells. ii) Semiallogeneic (C3BF1) T cells cooperated successfully with parent-type (C3H) B cells developed in parent-type syngeneic chimeras (C3H/C3H), whereas parent-type (C3H as well as C57BL) T cells failed to cooperate with F1 (BC3F1) B cells developed in F1 syngeneic chimeras (BC3F1/BC3F1). iii) T cells obtained from C57BL/C3H or C57BL/C3BF1 chimeras, which were most likely donor (C57BL)- derived, cooperated successfully with C3H-derived B cells developed in C3H/C3H chimeras. iv) Evidence was obtained suggesting that stimulation of antibody response by allogeneic effect in the absence of syngeneic or semisyngeneic helper T cells did not take place in this experimental system. v) With the use of congenic resistant strains, it was shown that alloantigens controlled by H-2 loci, in particular by the K-I region of this gene complex, constituted the barrier of cooperative interaction between histoincompatible T and B cells. vi) Cooperation between H-2 compatible, non-syngeneic T and B cells was also disturbed in varying degrees depending on the strain combinations, thus indicating that cell surface antigens controlled by non-H-2 loci also had a significant role for the cooperative interaction between T and B cells. Problems associated with these findings were discussed.

[Absorption, distribution and excretion of 14C-josamycin and 14C-josamycin propionate in rats (author's transl)]

Abosrption, distribution and excretion of 14C-josamycin (JM) and 14C-josamycin propionate (JM-P) were studied in rats by measuring both antibacterial activity and radioactivity. 1. In antibacterial activity, plasma and tissue concentrations of JM-P showed a similar tendency to those of JM. Those concentrations of JM reached a peak at 1 hour after administration with a subsequent rapid decrease, while the peak level of JM-P appeared 2 approximately 4 hours after administration and then fell down very slowly. 2. In radioactivity, oral administration of JM-P rapidly produced a very high plasma and tissue concentrations which were in lung, liver, kidney and spleen more than twice those of JM. These results showed that when given orally, JM-P is well absorbed with distributions at high concentrations especially in lung, liver, and kidney and spleen. 3. The ratios of bioactivity/radioactivity in JM administration were the highest in lung and the lowest in liver at 1 hour after. But those of JM-P were generally much lower than those of JM because of higher distribution of JM-P radioactivity into tissues. 4. Four days after oral administration of JM and JM-P, 23.1% and 21.8% of the given radioactivity were recovered respectively from urine. However, the antibacterial activities recovered were 0.40% for JM and 0.65% for JM-P. 5. Biliary recoveries of JM and JM-P were 17.2% and 12.1% of administered radioactivity 2 days after oral administration. On the other hand, 0.47% of JM and 0.17% of JM-P were excreted into bile as antibacterial activity. These results showed that JM and JM-P were excreted into rat urine and bile as some metabolites with less biological activity. 6. The amounts of JM and JM-P recovered from feces were 75.7% and 60.2%, respectively, of the orally given radioactivity. The amount of radioactivity recovered from expiration air was about 1% of either orally given JM or JM-P.

Determination of a new cerebral vasodilator 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-[2-(N-benzyl-N-methylamino)]-ethyl ester 5-methyl ester hydrochloride (YC-93) in plasma by electron capture gas chromatography

A highly sensitive method for the quantitative determination of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-[2-(N-benzyl-N-methylamino)]-ethyl ester 5-methyl ester hydrochloride (YC-93) in plasma is described. After extraction, YC-93 was oxidized to a pyridine analogue with nitrous acid and detected by electron capture gas chromatography. The sensitivity was 2-3 ng/ml, which is sufficient to determine plasma concentrations of YC-93 after oral administration of clinical doses to humans.

The radiosensitivity of T and B lymphocytes in mice

The radiosensitivity of T and B lymphocytes in spleens of specific pathogen-free C3Hf/HeMs male mice was studied by the direct and indirect immunofluorescence technique. It was found that the radiobiological parameters characterizing the survival curve of Bpsi lymphocytes were DO = 200 R and n = 1-00. The T lymphocytes, on the other hand, were shown to consist of two distinct subpopulations with respect to their radiosensitivity. The radiobiological parameters of the radiosensitive fraction of T lymphocytes were Dq = 185 R, DO =195 R and n = 2-50. The DO value of the radioresistant T lymphocyte subpopulation was practically unmeasurable. It was estimated that approximately 8 per cent of the T lymphocytes present in the spleen of normal C3Hf mice belonged to this radioresistant subpopulation.