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Biomedical subjects

T Oku

Publications and source records attributed to T Oku.

At least 181 records · Page 10Linked to original sources
PubMed1984

Mode of rat cecal enlargement induced by a short-term feeding on glucomannan.

The increase in wet weight of rat cecum was evident at 16 hr of glucomannan ingestion and continued until 184 hr (the longest period observed in this experiment), reaching about 2.5-fold. The ratios of total protein/DNA and RNA/DNA were both always higher in cecum of rats fed glucomannan than the control group (0 hr). During the initial 40 hr, no significant change in total DNA content was observed with the increase in total protein and RNA. Furthermore, the incorporation rate of [3H]thymidine in cecal DNA was even lower in the glucomannan feeding than the control (0 hr) during the initial 40 hr. After 88 hr of the experiment, however, a significant increase in the synthetic rate of DNA was found as well as [14C]leucine incorporation into total protein. It was discussed that a hypertrophic change in rat cecum was initially induced by glucomannan ingestion and was followed by hyperplastic growth under continuous exposure of glucomannan.

Animals↗
PubMed1984

Interferon counteracts pyrimidinone-induced hyporeactivity and the combined treatment has antitumor effect in mice.

A potent interferon (IFN) inducer, 2-amino-5-bromo-6-phenyl-4-pyrimidinone (ABPP), induced hyporeactivity in mice, and so IFN induced by subsequently administered ABPP was reduced even 120 hr after the first administration of ABPP. This hyporeactivity was counteracted by the injection of IFN (10,000 IU or more) 3 hr before the subsequent administrations of ABPP. Since the injection of more than 5,000 IU/mouse of IFN 3 hr before an administration of ABPP enhanced the circulating IFN titer, the priming effect in vivo by IFN may result in the reduction of hyporeactivity. Administrations of ABPP (200 mg/kg or 500 mg/kg) at intervals of 2 days and the injection of IFN (25,000 IU/mouse) 3 hr before each administration of ABPP to neuroblastoma-bearing A/J mice reduced the mortality and completely cured 40% of the mice in each combined therapy group. These results suggest that the combined use of the IFN inducer with IFN may be available for patients with neoplasm or viral infection.

Animals↗
PubMed1984

Reduced resistance to experimental viral and bacterial infections of mice treated with polychlorinated biphenyl.

When mice given diet containing 100, 200 or 400 micrograms of polychlorinated biphenyl (PCB) per g, or PCB-free diet for 21 days were inoculated intranasally with influenza virus, the mortality was higher in some groups given PCB than in the control group. When Staphylococcus aureus was inoculated intraperitoneally into mice given a diets with or without PCB, a significant difference was observed in the mortalities in the groups. Subcutaneous injection of S. aureus also caused a larger subcutaneous abscess in the mice given diets containing PCB than in those given control diet. Thus, it is suggested that PCB ingestion reduces host resistance to systemic or local infection with viruses or bacteria.

Administration, Oral↗
PubMed1983

Stimulatory effect of calcium on photoactivation of the water oxidation system in dark-grown spruce chloroplasts.

The water-oxidation system in chloroplasts from Picea abies leaves grown without light was activated and stabilized upon exposure of the isolated chloroplasts to weak light. The rate of electron transport from diphenylcarbazide to 2,6-dichloroindophenol in the photosystem II remained constant. Ca2+ added to the chloroplast suspension was incorporated into thylakoid membranes during illumination and strongly stimulated the photoactivation of latent water-oxidation system but not electron transport in photosystem II. It is concluded that the site which requires Ca2+ and is activated by light is the water-oxidation system.

Calcium↗
PubMed1983

Prolongation by interferon preparation of the survival time of mice implanted with differentiation-inducible mouse myeloid leukemia cells.

The effect of L-cell interferon (IFN) preparation on the survival times of mice implanted with two different clones (T-22 and R-4) of mouse myeloid leukemic M1 cells were examined. T-22 cells, but not variant R-4 cells, can be induced to differentiate in vitro or in vivo into macrophages and granulocytes. In vitro growth of R-4 cells was markedly suppressed by IFN, but that of T-22 cells was resistant to IFN. The survival times of mice with implanted T-22 cells were prolonged by treatment with IFN but those of mice with implanted R-4 cells were not.

Animals↗
PubMed1983

Evaluation of CT in the diagnosis of congenital choanal atresia.

A six-year-old female with congenital bilateral choanal atresia was examined by CT (computed tomography) and contrast radiography. CT clearly demonstrated the existence of choanal atresia, and differentiated osseous stenosis from membranous stenosis in the choanae. CT may be the first choice of radiological examination for the pre-operative diagnosis of congenital choanal atresia.

Child↗
PubMed1983

Atypical ("pseudosarcomatous") cutaneous histiocytoma.

We report a patient with a cytologically atypical hemosiderotic histiocytoma that histologically suggested a sarcoma. The lesion is differentiated from atypical fibroxanthoma and fibroxanthosarcoma. We wish to emphasize the benign nature of this variant of histiocytoma whose extreme cellular atypicality may simulate a sarcoma.

Culture Techniques↗
PubMed1983

[Effect of interferon on mouse glioma].

Mouse interferon (IFN) induced in L 929 cells by Newcastle disease virus was examined for its effect on the growth of mouse brain tumor cell line. In this study, we used subcutaneously transplanted 203 Glioma model, which had been originally induced by methylcholanthrene in C 57 BL mice. After subcutaneous transplantation, intraperitoneal administration of IFN was started by following schedule; 5 X 10(3) IU twice a week, 5 X 10(4) IU twice a week, 2.5 X 10(5) IU twice a week, 5 X 10(3) IU every day and 2.5 X 10(4) IU every day. In all groups treated by IFN intraperitoneally, no inhibition of the tumor growth was seen. On the other hand, natural killer (NK) activity was augmented by IFN treatment. Therefore, we considered that augmentation of NK activity was not directly correlated with the antitumor effect of IFN. Then, local administration was examined. After subcutaneous tumor was recognized, 2.5 X 10(4) IU of IFN was injected intratumorally every day. About 20 days later, the tumor decreased its size less than that treated by local injection of saline. It was suggested that the local administration of IFN might be better than the systemic administration.

Animals↗
PubMed1982

Psoriatic leukotactic factor. Further physicochemical characterization and effect on the epidermal cells.

A leukocyte chemotactic factor with a molecular weight of around 12,500 daltons is found in large amounts in psoriatic scales. Except for complement-activated serum none of the extracts prepared from individual contaminants found in psoriatic scales showed an elution pattern similar to that of the psoriatic leukotactic factor (PLF) by Sephadex G-75 chromatography. Checkerboard experiments showed that PLF was highly chemotactic and mildly chemokinetic for polymorphonuclear leukocytes (PMNs). Purification of PLF yielded a cationic peptide fraction similar to that of anaphylatoxin. Intradermal injection of a potent PLF solution into guinea pigs produced degenerative changes in the epidermis within 24 h, particularly in the differentiated cells of the upper epidermis. It increased epidermopoiesis as assessed by incorporation of 3H-thymidine. Planimetric analysis of the epidermis revealed a marked increase in epidermal thickness after 5 days. Since PLF per se did not influence the proliferative capabilities of isolated basal cells or exert any damaging effect on differentiated epidermal cells in human epidermal cell culture, we speculated that PLF induced the advent of PMNs abound with hydrolytic enzymes and toxic substances, which were responsible for the damage of the upper epidermis resulting in the formation of parakeratosis and of acanthosis.

Animals↗
PubMed1982

Duct, exocrine, and endocrine components of cultured fetal mouse pancreas.

Twenty to twenty-two days postcoitum mouse fetal pancreas organ bits were cultured on the dermal surface of irradiated pigskin as a substrate. The medium used for long term culture consisted of Eagle's Minimum Essential Medium with the addition of 10% bovine serum, 0.02 U/ml insulin, 0.025 microgram/ml glucagon, 3.63 microgram/ml hydrocortisone, 100 microgram/ml soybean trypsin inhibitor or 10(-8) M atropine. When the medium lacked trypsin inhibitor or atropine but contained the three hormones, the pigskin support began to be destroyed after 2 to 4 wk in culture. Thereafter, the cultured cells could not grow and survive on the digested pigskin. When 10(-6) M atropine was added to the medium, amylase secretion from cultured cells and destruction of pigskin were inhibited completely but pancreas cells could not grow or survive. In contrast, 100 microgram/ml soybean trypsin inhibitor or 10(-8) M atropine permitted cell growth, permitted amylase secretion from the cultured acinar cells, and prevented the destruction of pigskin. Under these conditions pancreas cells migrated or grew or both from the organ bits onto the surface of the pigskin dermis and organoid aggregations formed. Hydrocortisone was needed to permit growth for more than 2 wk. Glucagon and insulin had additive effects. Light and electron microscopic observations indicated the culture of at least five kinds of cells, i.e., duct, acinar, centroacinar, endocrine, and mesenchymal. The majority of cultured cells were duct cells and acinar cells. There were few mesenchymal cells. Mouse pancreas cells were cultured for at least 12 wk by this method.

Amylases↗
PubMed1982

Elimination of polynucleotide-induced hyporeactivity in mice treated with interferon and antitumor therapy.

Polyriboinosinic-polyribocytidylic acid (poly I:C) (100 microgram) induced hyporeactivity to interferon production 24, 48 and 72 hr after the injection. This hyporeactivity was eliminated by the injection of mouse brain interferon (more than 10,000 IU) 3 hr prior to the second injection of poly I:C. Even the hyporeactivity caused by the repeated administration of poly I:C was eliminated when interferon was injected 3 hr before each administration of poly I:C. It was surmised that one of the causes for the elimination of hyporeactivity may be the priming effect effect of interferon in mice. By utilizing the eliminating effect which interferon has on the hyporeactivity caused by poly I:C, the synergistically suppressive effect of interferon and poly I:C on the mortality and tumor growth in the neuroblastoma-bearing mice was found. These results suggest that the combined use of interferon and interferon-inducer may be applicable to cancers or viral diseases in humans.

Animals↗
PubMed1982

Mechanism of inhibitory effect of unavailable carbohydrate on intestinal calcium absorption.

The effect of unavailable carbohydrates on the intestinal absorption of calcium was studied in rats raised for 7 or 8 weeks on diets containing 10 or 20% of cellulose, glucomannan, or pullulan. The following results were obtained a) Body weight gain was diminished more severely in glucomannan groups than in cellulose groups. b) Serum calcium levels were slightly lower in all groups fed unavailable carbohydrates, whereas serum inorganic phosphorus levels were similar to that of the control group. c) There was a significant reduction of bone ash from rats fed glucommanan or cellulose with 620 glycoside bonds. d) Calcium transport measured in the everted duodenal sac remarkable decreased in the glucomannan 20% group, but slightly increased in the cellulose groups. e) Calcium binding activity was lowered significantly in all groups fed unavailable carbohydrates. f) Alkaline phosphatase and sucrase activities in the duodenum were also markedly decreased by prolonged intake of unavailable carbohydrates. These results indicate that inhibitory effect of unavailable carbohydrates on intestinal calcium absorption is partially due to the loss of calcium binding protein caused by gastrointestinal transit of large amounts of undigested substances.

Animals↗
PubMed1982

Calcium-binding proteins in bovine milk: calcium-binding properties and amino acid composition.

The Ca2+-binding properties and amino acid compositions of two calcium-binding proteins (mCaBP-3 and mCaBP-4) purified from bovine milk were studied. mCaBP-3 was identified as a Ca2+-bound type and mCaBP-4 as a Ca2+-free type by means of ion-exchange chromatography on a DEAE-Sephadex A-25 column. In polyacrylamide gel disc electrophoresis, both mCaBP-3 and mCaBP-4 had the same mobility of Rf = 0.73 and the addition of 5 mM CaCl2 to the electrode buffer decreased the mobility from Rf = 0.73 to Rf = 0.49. mCaBP-3 and mCaBP-4 consisted of 120 and 122 amino acid residues, respectively. The molecular weights were 13,758 and 13,967, respectively. The amino acid compositions of the two milk CaBPs very closely resembled each other. Both milk CaBPs were rich in aspartic acid, glutamic acid, leucine and lysine, but did not contain trimethylated lysine and amino sugar. An interesting feature is that each milk CaBP contained eight cysteine sulfone and three tryptophan residues per molecule. From these results, it is suggested that mCaBP-3 and mCaBP-4 are identical protein and that mCaBP-3 is formed from mCaBP-4 by means of a conformational change by binding of Ca2+. Thus, mCaBP-3 is a holoprotein and mCaBP-4 is an apoprotein. Furthermore, it is suggested that milk CaBP is different from calmodulin, troponin C and vitamin D-dependent calcium-binding protein.

Amino Acids↗