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Biomedical subjects

M Terada

Publications and source records attributed to M Terada.

At least 19 recordsLinked to original sources
PubMed1979

Induction of erythroid differentiation of murine erythroleukemia cells by nicotinamide and related compounds.

Nicotinamide and its analogues were evaluated for their activity as inducers of differentiation of murine erythroleukemia cells in culture. N'-Methylnicotinamide was the most effective of the compounds tested; at its optimal concentration it was more effective than dimethyl sulfoxide. With 8-10 mM N'-methylnicotinamide, almost all the cells contained hemoglobin (benzidine-reactive) after a 60-hr culture. Commitment to differentiate, assayed by transfer of the cells to semisolid medium without inducers, occurred much earlier and was more extensive with N'-methylnicotinamide than that with dimethyl sulfoxide or nicotinamide. Increase in globin mRNA was greater in the cells cultured with N'-methylnicotinamide than in cells cultured with dimethyl sulfoxide or nicotinamide. The relationship between the inducing activities of nicotinamide analogues and their effect on poly(ADP-ribose) polymerase in vitro was studied. All the compounds studied that had strong inhibitory effects on poly(ADP-ribose) polymerase in vitro induced differentiation of erythroleukemia cells in culture. This property is not a prerequisite of inducers; N'-methylnicotinamide did not inhibit the enzyme in vitro.

Animals↗
PubMed1979

[Clinical investigation on a new penicillin derivative, bacampicillin (author's transl)].

A clinical investigation was carried out on a new penicillin derivative, bacampicillin with the following results. (1) Clinical effect--Bacampicillin was administered orally to 18 patients with acute simple cystitis, acute simple pyelonephritis, chronic prostatitis and acute gonorrhoic urethritis. Daily doses ranged from 750 mg to 1,000 mg. The administration continued for 4 to 14 days. Clinical effect was excellent in 10 patients and good in 5 patients. (2) Side effect--Side effects were noticed in 4 patients, one was allergic eruption and other 3 were gastralgia. In a patient the drug was discontinued to administer.

Adult↗
PubMed1979

Alteration in binding of dexamethasone to glucocorticoid receptors in regenerating rat liver after partial hepatectomy.

Changes in binding of dexamethasone (9 alpha-fluoro-11 beta, 17 alpha, 21-trihydroxy-16 alpha-methylpregna-1,4-diene-3,20-dione) to its receptors in regenerating rat liver after 70% hepatectomy were examined. Specific receptors for dexamethasone in the liver remnants of adrenalectomized rats decreased significantly during the period of DNA synthesis after 70% hepatectomy; then, they increased to above the control values between Days 4 and 7 after partial hepatectomy and subsequently returned to the control values. During the period of DNA synthesis, decreased binding was observed in partially hepatectomized rats with or without adrenals, but later enhanced binding was not prominent in rats with adrenals.

Adrenal Glands↗
PubMed1978

Erythroid cell differentiation.

Normal and transformed erythroid cell precursors provide the opportunity for study of a number of problems relevant to the regulation of proliferation and differentiation in a developmental system. Evidence is presented which suggests that the hormone, erythropoietin, has a primary role in regulating precursor cell proliferation. A wide variety of chemicals can modify the rate at which proliferating transformed precursors initiate expression of the genetic program characteristic of terminal erythroid differentiation. Several sites of inducer action, including the plasma membrane and chromatin, are suggested as part of the pathway which leads to the complex pattern of gene transcription responsible for differentiation.

Acetamides↗
PubMed1978

Regulation of differentiation in normal and transformed erythroid cells.

Studies are described employing two erythropoietic systems to elucidate regulatory mechanisms that control both normal erythropoiesis and erythroid differentiation of transformed hemopoietic precursors. Evidence is provided suggesting that normal erythroid cell precursors require erythropoietin as a growth factor that regulates the number of precursors capable of differentiating. Murine erythroleukemia cells proliferate without need of erythropoietin; they show a variable, generally low, rate of spontaneous differentiation and a brisk rate of erythropoiesis in response to a variety of chemical agents. Present studies suggest that these chemical inducers initiate a series of events including cell surface related changes, alterations in cell cycle kinetics, and modifications of chromatin and DNA structure which result in the irreversible commitment of these leukemia cells to erythroid differentiation and the synthesis of red-cell-specific products.

Cell Cycle↗
PubMed1978

Induction of murine erythroleukemia differentiation by actinomycin D.

Murine erythroleukemia cells are induced to differentiate by 0.5-5 ng of actinomycin D per ml. Murine erythroleukemia cells cultured with actinomycin D prolong cell doubling time but achieve the same density after 5 days as cells without inducer. Actinomycin D causes over 95% of the cells to become benzidine-reactive. [(3)H]Actinomycin D uptake into DNA can be detected within 2 hr and reaches a maximum (approximately 0.1 pmol/10(6) cells) by 10-12 hr. It is estimated that about one out of 10(5) dG.dC pairs is bound to actinomycin D. Commitment to differentiation, assayed by transfer of cells to culture without inducer, was detected as early as 5 hr. Unlike Me(2)SO, which causes a transient prolongation in G(1) at about 15-20 hr, cells cultured with actinomycin D show a more sustained increase in the proportion of the cells in G(1). Globin mRNA accumulation was detectable by 19 hr in culture. Alteration in DNA stability in alkaline sucrose gradients was detected by 19 hr. Actinomycin D induces synthesis of Hb(maj) and Hb(min) in approximately equal amounts. A decrease in rates of synthesis of RNA, DNA, and total protein occurs in cells cultured with actinomycin D, as well as in cells cultured with Me(2)SO. No evidence for an early action of actinomycin D at the plasma membrane was obtained by measurement of changes in cell volume or (86)RbCl uptake. Taken together, the present results indicate that actinomycin D is a potent inducer of differentiation of murine erythroleukemia cells and suggest that the target of its effect may be at the level of DNA.

Animals↗
PubMed1978

Synthesis of globin mRNA in relation to the cell cycle during induced murine erythroleukemia differentiation.

The relationship between the synthesis of globin mRNA and the phase of cell cycle was examined in synchronized murine erythroleukemia cells. Cells were synchronized with respect to the cell division cycle either by culture with 2 mM thymidine or 2 mM thymidine followed by 0.5 mM hydroxyurea, which caused cells to accumulate in late G1 or early S (referred to as G1/S boundary). Cells were induced to erythroid differentiation by culture with 280 mM dimethyl sulfoxide or 4 mM hexamethylene bisacetamide. These inducers do not alter the progression of cells from the G1/S boundary through S, G2, and M, but do cause prolongation of the subsequent G1 phase. Accumulation of newly synthesized globin mRNA is first detected when cells are in this G1 phase.

Acetamides↗
PubMed1978

Fundamental studies on physiological and pharmacological actions of L-ascorbate 2-sulfate. VI. Effects of L-ascorbate 2-sulfate on lipid metabolism in guinea pigs.

Effects of L-ascorbate 2-sulfate (AAS) on lipid metabolism were studied in guinea pigs maintained on diet I with sufficient L-ascorbic acid (AA) supplement or on diet II without AA supplement. AAS(300 mg/kg) inhibited an increase in serum and liver levels of lipids to a greater degree than AA (175 mg/kg), a reference compond, in hyperlipidemic guinea pigs induced by cholesterol feeding with diets I or II. AAS also induced a decrease in serum and liver levels of lipids in guinea pigs which had been previously maintained for 6 weeks on diet II containing 1.0% cholesterol. AA administration significantly increased AA level in various organs of animals maintained on both the diets containing cholesterol. It also rectified the AA level lowered by previous maintenance on diet II containing cholesterol. AAS showed a slight AA replacing effect on the AA level. Both AA and AAS exerted preventive and curative effects on several symptoms due to chronic AA deficiency.

Animals↗
PubMed1978

Fundamental studies on physiological and pharmacological actions of L-ascorbate 2-sulfate. V. On the hypolipidemic and antiatherosclerotic effects of L-ascorbate 2-sulfate in rabbits.

Effects of L-ascorbate 2-sulfate (AAS) on lipid metabolism and on pathological changes of aorta and visceral organs were investigated in cholesterol fed rabbits, with ascorbic acid (AA) and clofibrate (CPIB) as reference compounds. Administration of AAS (300 and 150 mg/kg) inhibited an increase in the levels of serum total cholesterol, free cholesterol, triglycerides and phospholipids caused by cholesterol feeding. A high dose of AAS prevented an increase of liver weight. An increase in the level of liver cholesterol was inhibited by a high dose of AAS. Both doses of AAS effectively prevented an accumulation of cholesterol in the aorta. The area rate of atheromatous plaque in aorta was less in specimens from both groups of AAS than in those from control I. Pathological changes in intima and media of aorta were milder in specimens from both groups of AAS. Developed of patholoigcal changes in arteries of various organs were prevented with both doses of AAS.

Animals↗
PubMed1978

Changes in DNA associated with induction of erythroid differentiation by dimethyl sulfoxide in murine erythroleukemia cells.

The Friend virus-infected murine erythroleukemia cell can be induced to differentiate along erythroid cells in culture with various compounds, including dimethyl sulfoxide. DNA from murine erythroleukemia cells cultured with dimethyl sulfoxide shows a decrease in sedimentation rate in alkaline sucrose gradients after alkali lysis of the cells. These changes can be detected as early as 27 hr after the beginning of culture. Similar results are observed with DNA of the cells cultured with other inducers, butyric acid and dimethylacetamide, but not with DNA from a variant cell line resistant to induction with dimethyl sulfoxide. Ultraviolet irradiation, which is known to cause similar changes in the sedimentation rate of DNA in alkaline sucrose gradients, induces differentiation of the murine erythroleukemia cells. These studies suggest that alterations in DNA may be related to events involved in the induction of differentiation of murine erythroleukemia cells by dimethyl sulfoxide.

Alkalies↗
PubMed1978

Restoration by adrenalectomy of weight and binding capacity of glucorcorticoid receptors of the thymus in AH 130 tumor-bearing rats.

The binding capacity of specific receptors for dexamethasone (11beta,17alpha,21-trihydroxy-9alpha-fluoro-16alpha-methyl-1,4-pregnadiene-3,20-dione) in the cytoplasm of the thymus of rats bearing AH 130 (solid-type) tumors decreased significantly during tumor growth. Adrenalectomy restored the binding capacity of the glucocorticoid receptors and the weight of the thymus to nearly the normal values in rats bearing tumors. The affinity of these receptors for dexamethasone was very low in rats bearing tumors, but it was also restored to nearly the normal value by adrenalectomy.

Adrenal Glands↗