共查询到20条相似文献,搜索用时 8 毫秒
1.
Keiya Ozawa Noriharu Sato Akio Urabe Fumimaro Takaku 《Biochemical and biophysical research communications》1984,123(1):128-132
The effects of retinoic acid (RA) on the proliferation and differentiation of normal myeloid progenitor cells (CFU-C) were studied. In general, RA at 10?10 to 10?6 M enhanced primary myeloid colony formation in the presence of colony-stimulating factor(s). However, macrophage colony formation was strongly inhibited by RA. This may be related to the finding that RA is able to differentiate bipotential HL-60 cells into granulocytes but not into macrophages. Moreover, secondary colony formation was always suppressed by the addition of RA to the primary cultures. It means that self-renewal capacity of CFU-C was suppressed by RA. This finding suggests that normal myelopoiesis will be suppressed eventually by RA. 相似文献
2.
OKY-1581 is an effective inhibitor of thromboxane synthesis and . The generation of thromboxane B2 (TxB2), prostaglandin E (PGE) and prostaglandin F (PGF) was measured following clotting and during platelet aggregation induced by collagen. The presence of OKY 1581 either or caused a reduction in TxB2 generation during clotting and platelet aggregation with a concomitant increase in PGE and PGF. The effect could be observed two hours after oral or subcutaneous administration of 5 to 100 mg per rabbit and lasted for 24 to 48 hours. The reduction in TxB2 was not accompanied by an inhibition of clotting or platelet aggregation. OKY-1581 appears to be a suitable agent for studying the role of TxB2 in atherosclerosis. 相似文献
3.
John Lough Susan Keay Jan L. Sabran Sidney E. Grossberg 《Biochemical and biophysical research communications》1982,109(1):92-99
Continuous treatment of cultured chicken myoblasts with partially purified chicken interferon (IFN) inhibited myotube formation and the expression of MM-creatine kinase (MM-CK) at day 3, followed by continued MM-CK inhibition and concomitant stimulation of BB-creatine kinase (BB-CK) at day 4. Inhibition of MM-CK was also seen in IFN-treated cells prevented from fusing with EGTA. The degree of inhibition at day 3 depended on IFN dose over a range of 2.5–250 international units (IU)/ml; there was no evidence of cytotoxicity. Thus, IFN appears to inhibit the expression of muscle-specific traits during myogenesis. 相似文献
4.
Aftab A. Ansari Masroor A. Baig Heinrich V. Malling 《Biochemical and biophysical research communications》1981,102(1):93-99
Lactate dehydrogenase-C (LDH-C) mRNA was purified from mouse testes and translated . First, the LDH-C synthesizing polysomes were isolated by double immunoprecipitation using specific anti-LDH-C and anti-horse immunoglobulin antibodies. Extraction of mRNA was made from the isolated polysomes using hot sodium dodecyl sulfate-phenol method at alkaline pH. In a wheat germ cell-free translation system, the mRNA coded for a polypeptide chain that could be immunoprecipitated with specific anti LDH-C antibody and comigrated with authentic LDH-C in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 相似文献
5.
Shigeru Taketani Rikio Tokunaga 《Biochemical and biophysical research communications》1980,92(4):1343-1347
When rat liver mitochondria labeled with [59Fe]heme were incubated with microsomes in the presence of cytosol, about 16 % of the heme in mitochondria was transported to microsomes during a 1 hr-incubation period. In the absence of cytosol, little heme was transported. DEAE-Sephadex column chromatography of the cytosol partially purified by pH 5.1 treatment and ammonium sulfate precipitation (45–65%) revealed that there were at least two proteins with a releasing activity from mitochondria via heme transport. 相似文献
6.
Uterine stage embryos collected from the hamster (8-cell) and cow (morula, early blastocyst) were monitored for development (embryo culture) and (embryo transfer) following premature removal of the zona pellucida.Removal of the zona pellucida did not significantly affect development to the blastocyst stage of (1) 8-cell hamster embryos (zonae removed by a combined enzymic-mechanical procedure), (2) bovine morulae (zonae removed by mechanical means only) (3) early bovine blastocysts (zonae removed by the enzymic-mechanical technique).Zona-free hamster embryos formed significantly fewer viable fetuses than did zona-intact embryos. The lower incidence of fetal development observed following transfer of zona-free 8-cell hamster embryos may have resulted in part from the formation of chimeras by fusion of these embryos . Such fusion was observed to occur between zona-free embryos placed in close proximity. The proportion of pregnancies resulting from transfer of bovine blastocysts cultured from zona-free morulae was similar to that of zona-intact embryos.In this study we have demonstrated that (1) enzymic and mechanical procedures used to remove zonae pellucidae from uterine-stage hamster and bovine embryos do not adversely affect subsequent development of these embryos and and (2) zonae pellucidae are not required for normal development of these embryos. These findings have implications for microsurgery of mammalian embryos and for embryo transfer. 相似文献
7.
David Scicchitano Anthony E. Pegg 《Biochemical and biophysical research communications》1982,109(3):995-1001
The demethylation of O6-methylguanine in double stranded DNA catalyzed by rat liver O6-methylguanine-DNA transmethylase was found to proceed much more rapidly when the DNA substrate was methylated to a high extent. When the content of O6-methylguanine in DNA was equal to 1 in 2000 guanines, the reaction was 90% complete within 2 min, but when the content was 1 in 500,000 it required 27 min at 37°C. These results suggest that the repair protein either moves along the DNA substrate or else has little selectivity for binding specifically to the sites containing O6-methylguanine rather than to the normal DNA. The repair of O6-methylguanine in rat liver occurred at rates comparable to those seen with the substrates alkylated to low extents and was virtually complete within 3 hours. These results provide strong evidence that this protein is the factor responsible for O6-methylguanine removal and explain the wide variation in time courses reported in the literature since substrates methylated to greatly different extents have been used for such experiments. 相似文献
8.
Yolk free blastoderms of chick embryo were incubated 3 or 22 hours with labeled pregnenolone, progesterone, 17-hydroxyprogesterone, dehydro-epiandrosterone, androstenedione, testosterone and estradiol-17β. Metabolites and unconverted substrates were found both in the incubation medium and in the cells. Enzymes responsible for identified conversions were: 17α-hydroxylase, 17-20-desmolase, Δ53β- and 3α-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase and 5α- and 5β-reductase. The results suggest that the steroid metabolizing enzyme activities found may reflect a more general ability of early embryonic cells. 相似文献
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10.
A hepatotoxic dose of bromobenzene (3 mmoles/kg) decreases hepatic glutathione concentration in rats by approximately 80% within 5 hr following ip injection. A major bromobenzene metabolite, p-bromophenol at a similar dose did not significantly alter hepatic glutathione levels compared to controls. Twenty four hr after administration, serum glutamate pyruvate transaminase (SGPT) levels were significantly increased by bromobenzene but not by p-bromophenol. After 14C-bromobenzene administration, a significant amount of covalently bound radiolabel was detected in liver, kidney and small intestine. A small amount of covalently bound radiolabel was also detected in the lung. After a similar dose of 14C-bromophenol, covalently bound radiolabel was found in liver (62% of the amount detected with 14C-bromobenzene) and smaller amounts were detected in kidney, small intestine and lung. These data are consistent with the view that the hepatotoxity and glutathione depleting ability of bromobenzene are mediated mainly by bromobenzene-3, 4-oxide rather than by chemically reactive metabolites of p-bromophenol derived from bromobenzene. Covalently bound radiolabel from 14C-bromobenzene, however, may be derived from both bromobenzene-3, 4-oxide and the nontoxic reactive metabolites of p-bromophenol. 相似文献
11.
Peter B. Schiff Andrew S. Kende Susan B. Horwitz 《Biochemical and biophysical research communications》1978,85(2):737-746
The plant derivative steganacin, an antitumor compound, blocks the replication of HeLa cells in mitosis. Steganacin inhibits microtubule assembly and is a competitive inhibitor of colchicine binding to purified tubulin (Ki = 3.1 μM). The structure-activity relationships of steganacin and a series of analogues are reported. 相似文献
12.
The binding of the radiobrominated neuroleptic brombenperidol in rat brain was studied. The accumulation of the radiolabeled neuroleptic was high in the striatum and relatively low in the cerebellum, cortex, and blood. Striatal binding of brombenperidol was saturable and displaced by subsequent administration of benperidol. The rationale for the development of 75Br-brombenperidol as a radiopharmaceutical for the non-invasive imaging of cerebral dopamine receptor areas is presented. 相似文献
13.
Sven Hammarström Kerstin Bernström Lars Örning Sven-Erik Dahlén Per Hedqvist Göran Smedegård Björn Revenäs 《Biochemical and biophysical research communications》1981,101(4):1109-1115
[5,6,8,9,11,12-3H6] Leukotriene C3 (5 μCi) was injected through a catheter into the right atrium of an anesthetized male monkey. Blood samples were drawn from the aorta via a second catheter. The concentration of tritium in blood decreased from 100 nCi/ml after 5 sec to 1 nCi/ml 15 min after injection, suggesting that leukotriene C3 was rapidly eliminated from the circulation. Chromatographic analyses of radioactive material in blood collected before recirculation had occurred (15 sec after injection) demonstrated that 40% of the radioactive material had been converted into two less polar metabolites. These products had the same chromatographic properties as leukotrienes D3 and E3, respectively. The results indicate that leukotriene C3 is rapidly transformed by monkey lung . Two minutes after injection, the component corresponding to leukotriene E3 was the predominating metabolite in blood. 相似文献
14.
W.A. Deutsch A.L. Spiering G.R. Newkome 《Biochemical and biophysical research communications》1980,97(3):1220-1226
The -isomer of the antitumor drug dichlorodiammineplatinum(II) [-Pt(II)] was tested for its abilty to introduce nicks (single-strand breaks) into supercoiled PM2 DNA. Whereas incubations up to 24 h show no indication of -Pt(II)-treated DNA having single-strand breaks, DNA interstrand cross-links were detected in the first 15 min of incubation. Furthermore, the formation of DNA interstrand cross-links was inhibited and fully reversed after incubation with 2 mM thiourea. 相似文献
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16.
By the use of close arterial injection of leukotrienes into the circulation supplying the upper cervical canine trachea, it has been possible to assess the secretogogue effects of leukotriene C4, and D4 on mucus secretion. Both LTC4 and LTD4 increased mucus secretion over baseline levels by a statistically significant level (p = < 0.05). LTD4 was more potent than C4 with relative potencies of 2500, 320, 630, and 500 based on hillock formation (a measure of secretion) at 1, 2, 3, and 4 minutes after injection. The overall difference in potency in this animal model of mucus production was LTD4 > C4 by 1000-fold. 相似文献
17.
Robert D. Koos Martin R. Clark Per O. Janson Kurt E.B. Ahrén William J. LeMaire 《Prostaglandins & other lipid mediators》1983,25(5):715-724
Prostaglandin (PG) levels in follicular fluid from preovulatory follicles of rabbit ovaries perfused were measured in order to compare PG changes in this model system with those that occur and in isolated, LH-treated follicles . One ovary from each rabbit was perfused without further treatment (control). The other ovary was exposed to LH (0.1 or 1 ug/ml) beginning 1 hour (h) after initiation of perfusion. Samples of perfusion medium were taken at frequent intervals for measurement of PGE, PGF, progesterone and estradiol 17β. The perfusions were terminated when the first ovulation occurred or appeared imminent as judged by changes in the size and shape of the follicles. Follicular fluid was then rapidly aspirated from all large follicles on both ovaries for PGE and PGF measurement.Ovulations occurred only in the LH-treated ovaries. Progesterone and estradiol levels were significantly elevated in the perfusion medium within 1 h of LH treatment in comparison to controls. PG levels in perfusion medium from the control and LH-treated ovaries were not different throughout perfusion and increased in both groups. In contrast, PG levels measured in follicular fluid from LH-treated ovaries were 4- to 5-fold greater than in fluid from control ovaries. It is concluded that ovulation induced by LH in this experimental model is accompanied by an increase in follicular PG levels similar to that seen in other and models. This difference in follicular PG levels between the LH-treated and control ovaries is, however, not reflected in the perfusion medium. 相似文献
18.
Uma Raju Susan Kfcdner Mortimer Levitz Alexander Kaganowicz Ancel Blaustein 《Steroids》1981,37(4):399-407
The metabolism of 3H-androsterone was studied in homogenates (fortified with uridine 5'-diphosphoglucuronic acid and andenosine 3'-phosphate 5'-phosphosulfate) of eighteen breast tumors, one muscle underlying the primary breast carcinoma and metastatic axillary lymph nodes from a patient with suspected primary breast cancer. The major metabolites identified were less polar than androsterone. On saponification these lipoidal derivatives afforded androsterone as the only product (3 to 48%). Unmetabolized androsterone and lesser quantities of epiandrosterone, 5α-androstane-3α,17β-diol and 5α-androstane-3,17-dione comprised the free steroid fraction. Androsterone glucosiduronate was isolated (0.17–4.1%) from eight breast tumor homogenates and from the node tissue incubation (17%). There was no apparent correlation between glucuronyltransferase activity and histopathology or estrogen receptor content. 相似文献
19.
A. Vardanis 《Life sciences》1976,19(12):1949-1956
The system described utilizes the abdominal integument of the grasshopper as the tissue and radioactive glucose, glucosamine or UDP-N-acetyl glucosamine as substrate. A micromethod is described that makes it possible to use as little as 2 μl total volume of incubation. After an initial lag period, incorporation rates become linear for at least 2 hrs. Cell disruption leads to immediate and complete loss of activity. 相似文献
20.
The quantity of organic acids ( lactic acid, acetic acid, propionic acid and butyric acid ) in the content of the gastrointestinal tract of germ-free and conventional rats and the effects of the organic acid on the motility of the gastrointestinal tract of rats were investigated.Organic acids were detected only in the gastrointestinal contents of conventional rats but not in those of germ-free rats.Lactic acid detected in the stomach of rats stimulated the motility of both small and large bowel while acetic acid, propionic acid and butyric acid found in the cecum stimulated the motility of the large bowel but not of small bowel. 相似文献