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1.
2.
Convenient extraction and radioimmunoassay methods for measurement of leukotrienes C4 and D4 (LTC4 and LTD4) in biological fluids are described. LTC4 or LTD4 in plasma was extracted with acetonitrile, and the extract was washed with dichloromethane then adjusted to pH 3.5 or 6.0, respectively. Each leukotriene was partially purified by using a C18-bonded silica cartridge and quantitated by radioimmunoassay. Amounts of LTC4 and LTD4 in the range of 0.025-1.6 ng could be assayed in plasma. This procedure was employed to examine the increase in plasma LTC4 (0.249 +/- 0.036 ng/ml) and LTD4 (1.399 +/- 0.235 ng/ml) of guinea pigs during intravenous challenge-induced anaphylactic bronchoconstriction, and the suppression of the increase of bronchoconstriction and leukotrienes by the administration of 5-lipoxygenase inhibitors such as E6080 (6-hydroxy-2-(4-sulfamoylbenzyl-amino)- 4,5,7-trimethylbenzothiazole hydrochloride), AA861 (2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone ) and phenidone. On the other hand, LTC4 and LTD4 were not detected in plasma after an inhaled challenge, though significant bronchoconstriction was provoked. It was concluded that the present study validates a new technique for quantitating plasma leukotrienes on the basis of pH and a suitable method for evaluating the pharmacological efficacy of 5-lipoxygenase inhibitors. 相似文献
3.
Rat renal glomerular epithelial cells (SGE1 cell line) can be maintained and grown continuously in serum-free medium supplemented with insulin, iron-saturated transferrin (Tr), selenium, bovine serum albumin (BSA), linoleic acid, and epidermal growth factor (EGF). Of the growth supplements used, Tr is essential for proliferation of the cells. In the present study, we describe the use of a unique iron-chelate complex, ferric cacodylate (Fe-Cac), positively charged molecules in neutral buffer, that could almost replace Tr in serum-free culture. It even stimulated the growth of SGE1 cells more efficiently than ferric chloride (FeCl3) and other iron-chelate complexes, such as ferric nitrilotriacetate (Fe-NTA) and ferric citrate (Fe-Cit). The growth-stimulatory activity of Fe-Cac was exerted at iron concentrations of more than 0.01 g/ml, whereas a 10-fold excess of iron concentration was required with FeCl3, Fe-NTA and Fe-Cit. We observed that SGE1 cells grew until confluent, then formed hemicysts (domes) in serum-free medium containing Fe-Cac, suggesting that Fe-Cac did not merely permit cell growth but also supported polarization and organization of the cells into a functional epithelial architecture. Moreover, since the stimulatory activity of Fe-Cac was completely abolished by desferrioxamine, a strong iron chelator, it is suggested that iron is crucial for growth of SGE1 cells. When the cells were treated with suramin, an inhibitor of cellular pinocytosis and endocytosis of a large spectrum of ligands including receptor-bound growth factors, growth-stimulatory activity of Tr was inhibited, whereas the activity of Fe-Cac was not affected. These results, taken together, strongly suggest that the growth-stimulatory activity of Fe-Cac is associated with iron delivery into the cells through the cell membrane by diffusion, which is different from Tr receptor-mediated endocytosis. The use of Fe-Cac for investigating iron-regulated cell proliferation is suggested. 相似文献
4.
T Isomura K Tamiya-Koizumi M Suzuki S Yoshida M Taniguchi M Matsuyama T Ishigaki S Sakuma M Takahashi 《Nucleic acids research》1992,20(20):5305-5310
We reported that the RFP gene encodes a protein with putative zinc finger domains and was involved in the activation of the ret proto-oncogene. To further characterize the RFP protein, we developed a polyclonal antibody against the product synthesized from a fragment of the RFP cDNA expressed in Escherichia coli. Western blot analysis showed that RFP was identified as a 58 kDa protein in cell lysates from four human and rodent cell lines and from mouse testis. In addition, a unique 68 kDa protein was detected in the testis. Using AH7974 (rat ascites hepatoma) and Raji (human Burkitt lymphoma) cells, we demonstrated strong association of RFP with the nuclear matrix. Furthermore, RFP solubilized from the nuclear matrix had DNA-binding activity although it appears to bind more preferentially to double-stranded DNA than to single-stranded DNA. These results thus suggest that RFP may play a role in molecular processes which occur in the nuclear matrix. 相似文献
5.
Freeze denaturation of enzymes and its prevention with additives 总被引:3,自引:0,他引:3
Freeze inactivation of LDH, MDH, ADH, G-6-PDH, and PK and its prevention with additives such as sodium glutamate and albumin were studied. LDH, MDH, ADH, G-6-PDH, and PK, each lost their activity during frozen storage at -20 degrees C. The speed of the inactivation differed in each. The stability of the enzymes increased with the increase of the enzyme concentration. Sodium glutamate and albumin prevented the freeze inactivation. While the activity of the LDH solution frozen without additives was almost lost during a day of frozen storage, those frozen with either glutamate (0.2 M) or albumin (0.1%) added decreased less quickly. The residual activity after 1 day was 50% the initial prefreeze value for the former and 10% for the latter, respectively. Combined use of glutamate and albumin prevented the inactivation the best and maintained the initial activity almost completely over 6 weeks. The enzymes tested lost some part of their activity when their solutions were diluted by the media. This inactivation was prevented to a significant extent by the addition of sodium glutamate and/or albumin to the diluting media. 相似文献
6.
Momoko Chiba Masakazu Kikuchi Chiharu Tohyama Masataka Nishikawa 《Biological trace element research》1990,25(2):137-147
To study effects of simultaneous administration of tin (Sn) and selenium (Se) on concentrations of several essential elements, mice were injected with either SnCl2 (ip) or Na2SeO3 (sc), alone or both compounds at a daily dose of 5 mumol/kg each for 12 consecutive days. Mice were sacrificed at 20 h after the last injection and concentrations of Sn, Se, Na, Ca, Zn, P, Fe, K, and Mg in the liver, kidney, spleen, pancreas, testis, seminal vesicle, lung, femoral muscle, and femoral bone were determined. In the control mice, Sn and Se concentrations were the highest in bone (0.69 micrograms Sn and 6.93 micrograms Se/g dry wt). Administered Sn was found to accumulate in all organs except the testis. Among the essential elements determined, Na was the most affected in terms of concentration in the organs and Mg was the least affected element in these organs. Among the organs tested, each elemental concentration in the pancreas was most affected. Simultaneous injections of Sn and Se appeared to keep the correlation coefficients between elements similar to those found in the control mice. 相似文献
7.
Indoor climate was assessed in an apartment in Isehara City, Kanagawa Prefecture, Japan, by use of a fungal index. The index represents the environmental (climate) capacity to allow fungal growth; it is determined by measuring the growth rate of a biosensor fungus, Eurotium herbariorum J-183. Differences in climate among various parts of the apartment (microclimate) and its changes could be clarified by using the index. The index in the entire apartment was high in summer, low in winter, and intermediate in spring and autumn. According to the part of the apartment, the index was high in water-associated areas and cool areas. This high fungal index in cool areas was caused by the air at the same absolute humidity showing an increase in the relative humidity with a decrease in temperature. Fungal contamination rapidly progressed in areas with a high fungal index in this apartment. A correlation was observed between the fungal index and fungal contamination. Therefore, areas susceptible to fungal contamination can be estimated by use of the fungal index. 相似文献
8.
Kumiko Ui Shoko Nishihara M. Sakuma S. Togashi R. Ueda Y. Miyata T. Miyake 《In vitro cellular & developmental biology. Animal》1994,30(4):209-216
Summary From the central nervous system ofDrosophila melanogaster 3rd instar larvae, eight continuous cell lines have been established (named ML-DmBG1 to 8). Using ML-DmBG2, single colony
isolation was carried out and six colonial clones were obtained. All reacted to the antibody to horseradish peroxidase, which
is a neuronal marker in insects. Acetylcholine, a known neurotransmitter inDrosophila, was detected in three of the colonial clones by high performance liquid chromatography. Therefore, it is concluded that
the established colonial clones are neural cells originating in the larval central nervous system. Among them, some variation
was observed with respect to morphology, acetylcholine content, and reactivity to anti-HRP. The variation may reflect the
heterogeneity of cells composing the central nervous system. 相似文献
9.
Minoru Kakeda Chiharu Ueguchi Hisami Yamada Takeshi Mizuno 《Molecular & general genetics : MGG》1995,248(5):629-634
10.
Putative morphogen, DIF, of Dictyostelium discoideum induces apoptosis in rat pancreatic AR42J cells
Yuzuru Kubohara Chiharu Kimura Kazuhiko Tatemoto 《Development, growth & differentiation》1995,37(6):711-716
We have recently shown that differentiation-inducing factor-1 (DIF-1) of Dictyostelium discoideum is capable of raising intracellular calcium concentration ([Ca2+ ]i ) and suppressing cell proliferation of rat pancreatic AR42J cells in a dose-dependent manner, and that DIF-1 at a concentration of 40 μmol/L is toxic to the cells. In this study, we have further characterized the cytotoxic effect of DIF-1 on AR42J cells and have analyzed the effect of DIF-1 on [Ca2+ ]i . In the presence of 40 μmol/L DIF-1, cells began to bleb after approximately 6 h, and most had died within 48 h. Biochemical analysis revealed that DNA fragmentation was accompanied by cell death. Monitoring the changes in [Ca2+ ]i induced by DIF-1, it was found that cells were able to adapt to stimulation with DIF-1 so that they did not respond to subsequent stimulation by DIF-1. These results indicate that DIF-1 induced apoptosis in AR42J cells probably via a cell signaling system. 相似文献