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Biomedical subjects

T Suda

Publications and source records attributed to T Suda.

At least 757 records · Page 42Linked to original sources
PubMed1986

[Study of the ameliorating effects of an enteral nutrient for liver failure on hepatic encephalopathy: effects of SF-1008C on plasma and brain free amino acids, intracerebral amine concentrations and electroencephalogram in portacaval shunted rats with ammonia loading].

The ameliorating effects of an enteral nutrient for liver failure (SF-1008C), which is enriched with branched-chain amino acids (BCAA) and includes few aromatic amino acids (AAA), were investigated. The blood ammonia, plasma and brain free amino acids, intracerebral amine concentrations and electroencephalogram were measured in portacaval shunted rats with 10% ammonium acetate (3 ml/kg, i.p.) (PCS) as a model of hepatic encephalopathy. The blood ammonia and plasma free amino acid concentrations in PCS rats were significantly increased in comparison to sham-operated (Sham) rats. Thus, the plasma BCAA/AAA ratio in PCS rats was appreciably reduced. Concomitant with the abnormal plasma amino acid concentrations, the brain free amino acid concentrations in PCS rats were markedly increased in comparison to the Sham rats. Moreover, the intracerebral tryptophan (Trp) and 5-hydroxyindol acetic acid (5-HIAA) concentrations were significantly increased, and the intracerebral dopamine (DA) concentration was significantly decreased in the PCS rats. The intracerebral serotonin (5-HT) and norepinephrine (NE) concentrations were, however, hardly changed. A smaller voltage for the electroencephalogram was used in the PCS rats than in the Sham rats. Abnormal plasma and brain free amino acid concentrations in PCS rats were normalized by oral administration of SF-1008C, and the low voltage electroencephalograms in the PCS rats were suppressed. On the other hand, abnormal plasma and brain free amino acid concentrations in the PCS rats were hardly normalized by oral administration of ED-AC, an elemental diet based on an amino acid composition of egg protein. These results suggest that SF-1008C affects brain free amino acids, intracerebral amine concentrations and electroencephalogram by ameliorating abnormal plasma free amino acid concentrations. Moreover, there is a highly significant correlation between the plasma BCAA/AAA ratio and the brain BCAA/AAA ratio, and this finding suggests that the plasma free amino acid patterns reflect the brain free amino acid patterns.

Amino Acids↗
PubMed1986

Characterization of immunoreactive corticotropin and corticotropin-releasing factor in human adrenal and ovarian tumours.

The distribution of immunoreactive ACTH (I-ACTH) and corticotropin-releasing factor (I-CRF) in the human adrenal was determined and these peptides were indentified in adrenocortical adenomas from patients with primary aldosteronism. Cushing's syndrome, and ovarian tumours and compared with the results in phaeochromocytomas. I-ACTH and I-CRF, mainly localized in the adrenal medulla from patients without endocrine disorders, showed a good correlation with the epinephrine concentrations. I-ACTH and I-CRF were present in all the above-mentioned tumours. Gel filtration of I-ACTH and I-CRF from these tumours showed the presence of large molecular weight forms of these peptides as well as authentic peptides. The trypsinization study of I-CRF from phaeochromocytoma suggested that such large molecular weight forms were the precursors of authentic CRF. High performance liquid chromatography showed I-CRF in these tumours to be similar to hypothalamic CRF. Phaeochromocytoma tissue slices incorporated [3H]leucine into ACTH and CRF. These findings raised the possibility that I-ACTH and I-CRF are synthesized and processed in phaeochromocytoma.

Adenoma↗
PubMed1986

Augmentation of antitumor immune response by trinitrophenyl (TNP)-reactive helper T-cells: enhanced induction of tumor-specific Lyt-1+2- T-cell-mediated delayed-type hypersensitivity from spleen cells of tumor-bearing mice by TNP helpers.

Spleen cells from X5563 tumor-bearing syngeneic C3H/HeN mice were stimulated in vitro with trinitrophenyl (TNP)-modified or unmodified X5563 tumor cells. TNP-reactive helper T-cells obtained from TNP-primed C3H/HeN mice were added to the above cultures in an attempt to augment the induction of anti-X5563 delayed-type hypersensitivity (DTH) responses. The DTH responses were measured by adoptive transfer of cultured cells together with unmodified X5563 cells into footpads of syngeneic mice. Cultures of spleen cells from tumor-bearing mice plus X5563 or TNP-modified X5563 cells failed to generate anti-X5563 DTH responses. In contrast, addition of TNP-helper T-cells to the cultures resulted in appreciable DTH as well as in cytotoxic responses to X5563 tumor cells. Demonstration of this immunity was dependent on the presence of TNP-X5563 tumor cells as stimulators during the culture period. The anti-X5563 DTH effector cells augmented by TNP helpers were found to be of the Lyt-1+2- phenotype and were tumor specific, since DTH responses were observed when the cultured cells were injected with X5563 but not when injected with another syngeneic tumor. These results demonstrate that TNP-helper T-cells are capable of augmenting the induction of tumor-specific Lyt-1+2- T-cell-mediated DTH responses from lymphoid cells of tumor-bearing mice upon the stimulation of TNP-reactive tumor cells. The results are discussed in relation to: a previously described tumor-specific immunotherapy model in which a growing tumor regressed by virtue of TNP helpers and the implications of augmenting induction of tumor-specific DTH responses in antitumor resistance.

Animals↗
PubMed1986

Enhancement by 1 alpha,25-dihydroxyvitamin D3 of chemically induced transformation of BALB 3T3 cells without induction of ornithine decarboxylase or activation of protein kinase C1.

We reported previously that 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], a hormonally active form of vitamin D3, markedly enhanced methylcholanthrene-induced transformation of BALB 3T3 A31-1-1 cells. When the cells were treated with methylcholanthrene (1 microgram/ml) for 72 h and then with 1 alpha,25(OH)2D3 (5 ng/ml) for 2 wk, the transformation frequency was 1.95 +/- 0.73 (SD) foci/dish in 8 independent experiments, which was about 20 times that in cultures treated with methylcholanthrene only. Even at a physiological concentration in plasma, i.e., 0.05 ng/ml, 1 alpha,25(OH)2D3 enhanced the transformation frequency significantly (P less than 0.001). 1 alpha,25(OH)2D3 was not cytotoxic but slightly inhibited growth of the cells. Cells treated with 1 alpha,25(OH)2D3 were thin and became arranged in a meshwork with wide intercellular spaces. These morphological changes were reversible. 1 alpha,25(OH)2D3 induced DNA synthesis in quiescent BALB 3T3 cells dose and time dependently, but this effect was less than that of 12-O-tetradecanoylphorbol-13-acetate. Unlike 12-O-tetradecanoylphorbol-13-acetate, 1 alpha,25(OH)2D3 did not interfere with the binding of epidermal growth factor or phorbol dibutyrate. 1 alpha,25(OH)2D3 did not induce ornithine decarboxylase. Moreover, it did not activate protein kinase C in quiescent BALB 3T3 cells or this enzyme isolated from mouse brain. BALB 3T3 cells and their transformants contain a specific cytosol receptor for 1 alpha,25(OH)2D3, but the binding sites of the transformants were fewer and had lower affinity than those of untransformed BALB 3T3 cells. These effects of 1 alpha,25(OH)2D3 were specific, because other derivatives of vitamin D3 induced the same effects only at 200 times or more higher concentrations.

Animals↗
PubMed1986

Induction of anchorage-independent growth of JB6 mouse epidermal cells by 1 alpha,25-dihydroxyvitamin D3.

1 alpha,25-Dihydroxyvitamin D3 [1 alpha,25(OH)2D3], a hormonally active form of vitamin D3, was shown previously to enhance chemically induced transformation of BALB 3T3 cells and Syrian hamster embryo cells. This report demonstrates that 1 alpha,25(OH)2D3, like phorbol ester tumor promoters, induces anchorage-independent growth of mouse JB6 epidermal cells. When plated on agar plates containing 1 alpha,25(OH)2D3 at concentrations higher than 0.05 ng/ml or 0.12 nM, JB6 cells formed colonies on the surface of agar plates dose dependently. This anchorage-independent growth was further confirmed by stimulation of DNA synthesis after liquefying the agar layer with NaI. A phorbol-ester resistant variant of JB6 cells was also resistant to 1 alpha,25(OH)2D3 in terms of induction of anchorage independency. Induction of anchorage-independent growth was specific for 1 alpha,25(OH)2D3: other derivatives of vitamin D3 also induced colony formation on agar plates but only at a higher concentration (500 ng/ml) and to much less extent than did 1 alpha,25(OH)2D3. JB6 cells were found to contain a receptor specific for 1 alpha,25(OH)2D3 with a Kd of 55.7 pM and Nmax of 102.5 fmol/mg protein, suggesting a receptor-mediated mechanism of the induction. The clone that was resistant to 1 alpha,25(OH)2D3 also contained the receptor. DNA-cellulose chromatography showed that a 1 alpha,25(OH)2D3-receptor complex interacted with DNA. In contrast to 1 alpha,25(OH)2D3, retinoic acid did not induce anchorage-independent growth of JB6 cells, but it inhibited the induction by 1 alpha,25(OH)2D3 when applied with it.

Animals↗
PubMed1986

Purified interleukin-3 and erythropoietin support the terminal differentiation of hemopoietic progenitors in serum-free culture.

We studied the effect of purified interleukin-3 (IL-3) and erythropoietin on colony formation by hemopoietic progenitors in serum-free cultures of spleen cells from 5-fluorouracil (5-FU)-treated mice. In the presence of IL-3 alone, most of the multilineage (three or more lineages) colonies did not contain erythroid cells. However, in the presence of IL-3 and erythropoietin, most of the multilineage colonies contained various numbers of erythroid cells. Replating experiments suggest that IL-3 maintains the growth of the progenitor cells, which could differentiate into erythroid cells. Erythropoietin facilitated the terminal differentiation and amplification of erythroid cells, although it did not sustain the growth of multipotential stem cells. Single-cell transfer experiments demonstrate that IL-3 supported the late stages of differentiation of neutrophils, macrophages, eosinophils, and megakaryocytes in the absence of lineage-specific factors. Therefore, IL-3 supports the differentiation of multilineage hemopoietic progenitors, and the terminal differentiation of most hemopoietic lineages, with the exception of the erythroid lineage.

Animals↗
PubMed1986

Action of carnosine and beta-alanine on wound healing.

In rats treat-given hydrocortisone to suppress healing, tensile strength of the skin at the site of an incision wound was significantly higher in rats locally treated with carnosine than in untreated animals. Similar effects on the tensile strength of the skin were observed by the administration of beta-alanine and histidine, but not of beta-alanine alone. Exogenous carnosine was degraded in the body by carnosinase and histidine decarboxylase to yield histamine. Since beta-alanine, the other degradation product of carnosine, was found to stimulate the biosynthesis of nucleic acids and collagen, histamine derived from carnosine is considered to have enhanced the process of wound healing by stimulating effusion at the initial stage of inflammation. Thus, the enhancement by carnosine of wound healing may be ascribed to stimulation of early effusion by histamine and of collagen biosynthesis by beta-alanine. The wound-healing effects of carnosine were further demonstrated by the observation that carnosine significantly increased granulation suppressed by cortisone, mitomycin C, 5-fluorouracil, and bleomycin.

Alanine↗
PubMed1986

[Immunoregulative effects of carnosine and beta-alanine].

Physiological factors involved in immunity and tissue repair with regulate homeostasis, a physiological function of the connective tissue, are as yet unidentified. We earlier detected the granulation-promoting action of carnosine, and reported on the acceleration of tissue repair in experimental as well as clinical studies. In that study, immunoregulatory effects of carnosine and beta-alanine were examined by the plaque-forming cell (PFC) count and delayed hypersensitivity reaction (DHR). The PFC value increased in mice pretreated with these agents. In these mice, PFC reaction to 2 X 10(7) SRBC was enhanced but that to 1 X 10(9) SRBC was suppressed. The agents also suppressed excess immunoreaction in immature mice but increased weakened immunoreaction in aged animals. Furthermore, the agents had the optimal doses for the enhancement of both PFC reaction to 1 X 10(8) SRBC and DHR to 1% picryl chloride. They also induced recovery of immunofunction suppressed by the administration of MMC. Carnosine and beta-alanine exerts immunoregulatory effects by activating both T and B cells. Our observations indicated that the agents not only promote tissue repair but also help maintain homeostasis and accelerate spontaneous healing.

Alanine↗
PubMed1986

[Immunoregulative effects of homocarnosine and gamma-aminobuthyric acid].

The effects of homocarnosine and GABA on antibody production (PFC reaction) and cellular immunity (delayed hypersensitivity reaction, DHR) were examined in vivo. In mice treated with these agents, PFC reaction to 2 X 10(7) SRBC was enhanced but that to 1 X 10(9) SRBC was suppressed; moreover, immunoreaction was reduced in immature mice (2-2.5 weeks old) but was increased in aged mice (30 weeks old or above). These agents had optimal doses on the PFC reaction in mice given 1 X 10(8) SRBC and DHR, and induced recovery of immunofunction suppressed by the administration of MMC.

Aging↗
PubMed1986

[Antineoplastic effects of carnosine and beta-alanine--physiological considerations of its antineoplastic effects].

Antineoplastic effects of carnosine (CAR) and beta-alanine (ALA), were examined in vivo using ddY mice implanted with the solid tumor Sarcoma-180. The sarcoma was treated with trypsin, 10(5) cells were implanted subcutaneously in the back of the animals, and CAR and ALA were administered subcutaneously 2 cm from the implantation site starting on the next day. The animals treated with ALA alone showed prolongation of survival to a T/C value of 132%; the growth of the tumor was inhibited and mortality reduced in those treated with CAR alone. Regression of the tumor was observed in the animals treated with either drug. The effects of these agents were enhanced when administered in combination with the non-specific active immuno-enhancing agent OK-432. More than half the animals treated with CAR and OK-432 survived the observation period (T/C greater than 218%), and survival was prolonged in those treated with ALA and OK-432 to a T/C value of 132%. The agents also showed potent antineoplastic effects on Sarcoma-180 when the tumor had been attenuated in vivo with mitomycin C (MMC).

Alanine↗
PubMed1986

Modulation of cell growth, differentiation, and production of interleukin-3 by 1 alpha,25-dihydroxyvitamin D3 in the murine myelomonocytic leukemia cell line WEHI-3.

The effect of 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3], the active form of vitamin D3, on the relation between cell growth and differentiation was examined in a murine myelomonocytic leukemia cell line WEHI-3 which is known to produce high levels of interleukin-3. 1 alpha,25(OH)2D3 markedly inhibited proliferation of WEHI-3 cells in a time- and dose-dependent manner. Flow cytometric analysis of the cell cycle by a double staining method using fluorescein isothiocyanate-conjugated anti-bromodeoxyuridine and propidium iodide revealed that 1 alpha,25(OH2D3 increased the proportion and the number of cells accumulating in the G0-G1 phase and decreased those in the S phase. The phenotype of the surface antigens of the cells was of the T-cell lineage, but the cells became positive in macrophage-associated surface markers (Mac-1 and Ia) after treatment with 1 alpha,25(OH)2D3. The vitamin induced phagocytic activity, appearance of Fc receptors, nitroblue tetrazolium-reducing activity, and nonspecific esterase activity, indicating that the vitamin induces the cells to differentiate into macrophages. Furthermore, 1 alpha,25(OH)2D3 inhibited interleukin-3 production by the cells in a time- and dose-dependent manner. These results suggest that 1 alpha,25(OH)2D3 inhibits proliferation of WEHI-3 cells by blocking transition of the cells from the G0-G1 to the S phase, resulting in induction of the G0-G1-arrested cells to differentiate into macrophages. The relation between the suppression by 1 alpha,25(OH)2D3 of cell growth and interleukin-3 production remains to be elucidated in the future.

Animals↗