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Biomedical subjects

J Mori

Publications and source records attributed to J Mori.

At least 91 records · Page 5Linked to original sources
PubMed1989

A possible mechanism of fever induced by Nocardia rubra cell wall skeleton (N-CWS) in experimental animals.

The characteristics of fever elicited by the cell wall skeleton of Nocardia rubra (N-CWS) and by lipopolysaccharide (LPS) were compared in rabbits, and the possible involvement of the antigenicity of N-CWS was investigated in guinea pigs. In rabbits, fever of more than 0.5 degree C developed after an intravenous (i.v.) injection of 10 micrograms/kg or more of N-CWS, and was monophasic with 30-100 micrograms/kg but biphasic with the highest dose of 300 micrograms/kg. LPS elicited fever with similar characteristics at doses of 0.01-0.1 microgram/kg. With both compounds, the fever was inhibited by indomethacin. Tolerance to N-CWS and LPS appeared after dosing with 30 or 0.1 micrograms/kg, respectively for 10 d. In guinea pigs sensitized with N-CWS, challenge with 1 or 10 micrograms/kg of N-CWS 10 d later, which did not induce fever in the nonsensitized animals, caused fever of more than 0.5 degree C, and delayed-type hypersensitivity (DTH) appeared. N-CWS also elicited fever in nonsensitized guinea pigs bearing N-CWS-sensitized lymphocytes or anti-N-CWS antibody; the fever was higher in the guinea pigs sensitized with the lymphocytes than in those with the anti-N-CWS antibody. In brief, single injections of N-CWS and of LPS elicited fever with similar characteristics, although the potency of N-CWS was weaker. With N-CWS, the fever is proposed to be triggered by the antigenicity of the compound itself, because doses as low as 1 or 10 micrograms/kg elicited fever along with immunological response in N-CWS-sensitized animals, but not in nonsensitized ones.

Animals↗
PubMed1989

Possible involvement of a tumor necrosis factor (TNF)-like mediator as an endogenous pyrogen in fever induction by Nocardia rubra cell wall skeleton (N-CWS).

Tumor necrosis factor (TNF), a cytokine produced in macrophages, also acts as an endogenous pyrogen (EP). To investigate whether TNF has a role in the fever induced by Nocardia rubra cell wall skeleton (N-CWS), the relationship between fever and TNF production was studied in guinea pigs. N-CWS injected i.v. to guinea pigs caused biphasic fever and had L-929 cell-killing activity which resembled that of TNF in the sera 30 min before the first phase of fever appeared. In vitro, L-929 cell-killing activity was demonstrated in the culture supernatant of guinea pig peritoneal macrophages pretreated with N-CWS, and the activity increased dependently on N-CWS concentration or culture duration. When the supernatant of the macrophages was fractionated by gel filtration and each fraction was assayed for fever-inducing and L-929 cell-killing activities, the fraction with the cell-killing activity also induced fever with characteristics similar to that by i.v. injection of N-CWS in guinea pigs. These results suggest that TNF acts as an EP on the fever induced by N-CWS in guinea pigs.

Animals↗
PubMed1989

Effect of FK973, a new antitumor antibiotic, on the cell cycle of L1210 cells in vitro.

Our previous study showed that FK973 (11-acetyl-8-carbamoyloxymethyl-4-formyl-14-oxa-1,11- diazatetracyclo[7.4.1.0(2,7)0(10,12)]tetradeca-2,4,6-trien-6 ,9-diyl diacetate), a novel substituted dihydrobenzoxazine, which is a derivative of the fermentation product of Streptomyces sandaensis No. 6897, had strong antitumor effects on experimental tumors in vitro and in vivo. In this report, we investigated its effect on the cell cycle of murine leukemia L1210 cells in vitro by means of DNA/5-bromo-2'-deoxyuridine double staining and compared these effects with those of other antitumor drugs. Both FK973 and mitomycin C arrested the cells in the G2 phase. Vinblastine arrested the cells in the M phase and cytosine arabinoside, in the G1 phase. Although FK973 and mitomycin C were shown to act on the cell cycle in a similar way, FK973 was slower in producing its effect. From the results, FK973 arrests the cells in the G2 phase, and it appears that FK973 must be converted into the activated form in the cells for the development of its antitumor effects.

Animals↗
PubMed1989

Suppression of lactation by pregnancy-dependent mammary tumors in GR/A mice.

Pregnancy-dependent mammary tumors (PDMT) in GR/A mice appear during pregnancy, disappear soon after parturition, and appear again during subsequent pregnancies. The retardation of pup growth, an indication of the level of milk production, was also observed with the advance of lactation numbers in this strain. This study was performed to elucidate the relationship between PDMT and lactational performance. At the end of the second pregnancy, mice were divided into two groups according to the presence of PDMT [PDMT(-) and PDMT(+) groups]. Although all PDMT disappeared within a day after parturition, the weight and growth of pups on Day 12 of lactation were significantly less in the PDMT(+) group than in the PDMT(-) group. Associated with this, the DNA and RNA contents of the mammary glands were apparently lower in the former than in the latter, although the differences were not statistically significant. There was little difference in mammary RNA/DNA ratio between groups. No difference was also observed between groups in endocrine organ weights, mother body weights, morphology of the mammary glands, adrenals and ovaries and plasma prolactin and progesterone levels. These results suggest that PDMT suppression of lactation is principally due to the retardation of mammary gland growth. Furthermore, no significant correlations were obtained between the size of PDMT and the parameters for mammary gland function. The data suggest that the development of PDMT per se is important for the retarded mammary gland growth.

Animals↗
PubMed1989

[Requirement for radiation shields of transportation pipe for on line inhalation gases from compact cyclotron in positron emission tomography].

In the unit housing of a compact cyclotron and positron emission CT (PET), positron emitting gas such as 15O, 11C, C15O2, C15O etc. is supplied from a cyclotron to a PET room through a transportation pipe with an appropriate shield to reduce positron annihilation radiation. Using lead or concrete shield blocks with various thicknesses, radiation leakage through the shield was measured by an ionization chamber type survey meter during continuous and constant supply of 15O gas of 1.85 GBq/min concentration which is the maximum dose for clinical use. The leakage radiation measured was 213.7, 56.0, 15.3, 5.0 muSv/week for lead shield with 1, 2, 3, and 4 cm thickness, respectively, and 193.3, 30.5 and 5.1 muSv/week for concrete shields with thickness of 10, 20, and 30 cm, respectively. The present study shows that to keep less than 300 muSv/week, which is the permissible dose rate of the boundary zone around the radiation controlled area by Japan Science and Technology Agency, it is required to use more than 8 mm thick lead shield or 7 cm thick concrete for continuous supply of 1.85 GBq/min 15O gas.

Carbon Dioxide↗
PubMed1988

Interstrand DNA-DNA and DNA-protein cross-links by a new antitumor antibiotic, FK973, in L1210 cells.

In our previous study FK973, a novel, substituted dihydrobenzoxazine (11-acetyl-8-carbamoyloxymethyl-4-formyl-14-oxa-1,11-diazatetracyclo+ ++ [7.4.1.0(2,7).0(10,12)]tetradeca-2,4,6-trien-6,9-diyl diacetate), had potent cytotoxic and antitumor effects on murine tumors and human tumors in in vitro and in vivo experiments. In the present study the mechanism(s) of the in vitro cytotoxic effects of the drug on tumor cells were studied. After 1-h exposure of L1210 murine leukemia cells to the drug, the concentration of FK973 required to inhibit cell growth by 50% was approximately 1 microM, which was threefold more potent than the concentration of mitomycin C required. DNA synthesis was selectively inhibited in the cells treated with FK973. Alkaline elution analyses showed that FK973 formed concentration- and time-dependent interstrand DNA-DNA and DNA-protein cross-links in the cells. On the other hand, no DNA single-strand breaks were observed in the cells treated with FK973. When isolated nuclei of L1210 were exposed to FK973 for 1 h, FK973 did not form detectable interstrand DNA-DNA cross-links. We propose that FK973 is activated in the cytoplasm of cells, and forms interstrand DNA-DNA and DNA-protein cross-links which may be important for the induction of its cytotoxicity.

Animals↗
PubMed1988

Important role of serotonin in the antitumor effects of recombinant human tumor necrosis factor-alpha in mice.

The possible involvement of chemical mediator(s) in the induction of the antitumor effects of recombinant human tumor necrosis factor-alpha (rTNF-alpha) on Meth A fibrosarcoma (Meth A) in mice was studied. On day 7 after intradermal implantation of Meth A in mice, rTNF-alpha caused tumor necrosis and inhibited the tumor growth. Ketanserin, cyproheptadine, and spiperone [serotonin (5-HT) receptor blockers] inhibited or attenuated the antitumor effects of rTNF-alpha, but the other types of receptor blockers tested (histamine H1 and H2, adrenaline alpha and beta, dopamine, and acetylcholine receptor blockers) did not. The large i.v. doses of 5-HT caused tumor necrosis and inhibited tumor growth in mice when given i.v. on day 7 but not when given on day 3 after Meth A implantation, which effects closely resemble those of rTNF-alpha. Its anti-tumor effects were completely inhibited by the 5-HT receptor blockers. 5-HT, like rTNF-alpha, showed no cytotoxicity against in vitro cultured Meth A cells. The results suggest that 5-HT is, at least in part, important for the induction of antitumor effects of rTNF-alpha on Meth A in mice.

Animals↗
PubMed1988

Antitumor activity and hematotoxicity of a new, substituted dihydrobenzoxazine, FK973, in mice.

FK973, a new, substituted dihydrobenzoxazine (11-acetyl-8-carbamoyloxymethyl-4-formyl-14-oxa-1,11- diazatetracyclo[7.4.1.0.0]tetra-deca-2,4,6-trien-6,9-diyl diacetate), was obtained by chemical modification of a novel antibiotic which was isolated from the fermentation products of Streptomyces sandaensis No. 6897. FK973 had cytotoxic effects against in vitro cultured human and murine tumor cells. FK973 in doses of 0.032-5.6 mg/kg (i.p.) had stronger antitumor activities and higher chemotherapeutic ratio than mitomycin C against such murine ascitic tumors as P388 and L1210 leukemia, B16 melanoma, M5076 reticulum cell sarcoma of ovarian origin, Colon 26 carcinoma, Ehrlich carcinoma, and MH134 hepatoma. In tests against murine and human solid tumors implanted s.c. in normal mice and nude mice, respectively, FK973 (i.v.) inhibited growth of murine tumors (M5076 sarcoma, Colon 38 carcinoma, B16 melanoma, and Lewis lung carcinoma) by 66-100% and human tumors (LX-1 lung, MX-1 mammary, and SC-6 stomach carcinoma) by 84-99%. In studies with drug-resistant P388 leukemia, FK973 was also effective against vincristine-resistant P388, moderately effective against mitomycin C (MMC)- and adriamycin-resistant P388, and partially effective against cyclophosphamide-resistant P388 cells in mice. Leukopenic effects of FK973 and MMC in mice were comparable at doses which gave antitumor activity almost equally. FK973 had no effect on the numbers of platelets and red blood cells, whereas MMC markedly decreased both. FK973 decreased the numbers of colony forming units in spleen and in culture and the effect was less than that of MMC. Therefore, FK973 may give weaker myelosuppression than MMC. The results suggest that FK973 will be a beneficial drug for the treatment of cancer.

Animals↗
PubMed1988

Recombinant human tumor necrosis factor-alpha: thrombus formation is a cause of anti-tumor activity.

In a previous study we showed that recombinant human tumor necrosis factor-alpha (rTNF-alpha) has no cytolytic effect on Meth A fibrosarcoma cells in vitro but that it has a strong anti-tumor activity in vivo. In the present work, we define the in vivo mode of action of rTNF-alpha on solid-form Meth A fibrosarcoma implanted intradermally (i.d.) in mice. rTNF-alpha exhibited strong anti-tumor activity when given intravenously (i.v.) 7 or 10 days after tumor implantation, but not when given 3 days after implantation. Light and electron microscopy showed that rTNF-alpha impaired microcirculation by producing fibrin-like substances in newly formed microcapillaries in 7-day-old tumor tissue. An anti-coagulant, dicoumarol, abrogated the effect of rTNF-alpha. Injection of carbon particles showed that the development of capillaries in 7-day-old tumors was more extensive than in 3-day-old tumors, and suggested that the anti-tumor activity of rTNF-alpha depends upon a fully developed fine network of induced capillaries in the tumor. Electron microscopy showed that rTNF-alpha increases the number of primary and secondary lysosomes in the cytoplasm of 7-day-old tumor cells. The results suggest that rTNF-alpha selectively stems the blood flow in newly formed microcapillaries, eventually leading to autolysis of the tumor cells.

Adenocarcinoma↗
PubMed1988

Effects of pituitary grafting on plasma and milk levels of prolactin, growth hormone and progesterone in mice.

Plasma and milk levels of prolactin, growth hormone (GH) and progesterone on days 12-13 of lactation were compared between C3H/He female mice grafted with isologous anterior pituitaries each under the kidney capsules 2-3 days after placing with males and intact controls. At the 1st lactation, both plasma and milk levels of prolactin were higher in the experimental mice than in the control, however, at the 2nd lactation, milk prolactin level of the former decreased to about 1/8 of that of the latter, whereas plasma prolactin level further elevated in the former. While plasma GH level was increased by pituitary grafting, milk GH level was slightly affected by the treatment at either the 1st or the 2nd lactation. There was only a small difference between the experimental and the control groups in either plasma or milk level of progesterone at the 1st and the 2nd lactations. Progesterone levels in plasma and milk were higher at the 1st lactation than at the 2nd lactation in both the experimental and the control groups. These results suggest that the transfer of plasma hormones into milk is not always free, but there may be any regulatory mechanism(s) in this process.

Animals↗
PubMed1988

Relationships between milk levels of hormones and growth or puberty of offspring in mice.

Milk levels of prolactin, growth hormone (GH) or progesterone on days 12-13 of lactation and their relationships with the growth or the puberty of offspring were examined in primiparous SHN mice. Milk prolactin level had negative correlations with the body weights on days 12 and 20, the growth rate between days 0 and 20 or the age and the body weight at vaginal opening of offspring. There was a significant correlation between milk GH level and the growth rate between days 0 and 12 of offspring. A positive correlation was also found between milk progesterone level and the age at vaginal opening. These results suggest that hormones in milk would have effects on the growth or the puberty of offspring.

Animals↗
PubMed1988

Augmentation of the response of mouse uterine epithelial cells to estradiol by uterine stroma.

The effect of estrogen on the in vitro growth of mouse uterine epithelial cells was assessed. Epithelial cells from the immature mouse uterus were successfully cultivated in a 1:1 mixture of Dulbecco's Modified Eagle's Medium and Ham's F-12 supplemented with insulin (5 micrograms/ml), transferrin (10 micrograms/ml), hydrocortisone (10(-7) M), BSA (2 mg/ml), and fetuin (1 mg/ml). Addition of 17 beta-estradiol in the range of 1-100 nM did not significantly change the total DNA content of the epithelial cells. A binding component of [3H]estradiol by cultured uterine cells was shown to be specific, saturable, and of high affinity. Kd values for specific binding by epithelial and stromal cells were 1.0-1.7 x 10(-10) M. Maximal specific binding was 0.74 and 2.3 fmol/micrograms DNA for epithelial and stromal cells, respectively. Treatment of epithelial and stromal cells for 4 days with 10 nM estradiol led to a 2- to 6-fold increase in progesterone receptor concentration. Treatment of epithelial and stromal cells in mixed culture for 4 days with 10 nM estradiol resulted in a significant increase in total DNA. That epithelial-stromal contact was critical for estradiol stimulation was shown by the fact that if the cell types were separated into two compartments which still allowed free media mixing, total DNA was not enhanced by estradiol. These observations are organized into a model for mitogenic action of estradiol that seems to reconcile observed disparities in the action of the hormone in vivo and in vitro.

Animals↗
PubMed1988

Effects of FR50948, a new orally active antiallergic agent, in experimental allergic models.

The antiallergic activity of sodium 10-(2,3-dimethyl pentanamido)-4-oxo-4H-pyrimido [1,2-C] quinazoline-3-carboxylate-hydrate (FR50948) was studied and compared with the activities of sodium cromoglycate (SCG) and lodoxamide. FR50948 had inhibitory effects on type I and type III allergic reactions, but not on type II and IV allergic reactions. FR50948 also had weak inhibitory effects on inflammation (carrageenin paw edema and adjuvant arthritis) and SRS release from rat neutrophils, but no antagonistic effects to histamine and serotonin. The inhibitory effect of FR50948 on IgE-mediated type I allergic reactions was essentially the same as those of SCG and lodoxamide, because FR50948 inhibited the histamine release from rat peritoneal mast cells and had cross tachyphylaxis with SCG in the rat PCA test. However, FR50948, like lodoxamide, had a stronger activity than SCG and was effective by the oral route, unlike SCG which was effective only by the parenteral route. Furthermore, the inhibitory effects of FR50948 on type III reactions and inflammatory reactions were much more potent than those of SCG and equal to those of lodoxamide, and the effect on IgG-mediated PCA was stronger than that of either reference drug. These results suggest that FR50948 will be beneficial in clinical use.

Animals↗