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1.
Ginkgo biloba extract inhibits oxygen species production generated by phorbol myristate acetate stimulated human leukocytes 总被引:3,自引:0,他引:3
J. Pincemail A. Thirion M. Dupuis P. Braquet K. Drieu C. Deby 《Cellular and molecular life sciences : CMLS》1987,43(2):181-184
Summary A Ginkgo biloba extract (Gbe) containing flavonoids, among other compounds, was tested for the release of activated oxygen species (
, H2O2, OH.) during the stimulation of human neutrophils (PMNs) by a soluble agonist. The extract slows down O2-consumption (respiratory burst) of stimulated cells by its inhibitory action on NADPH-oxidase, the enzyme responsible for the reduction of O2 to
. Consequently, superoxide anion (
) and hydrogen peroxide (H2O2) production is significantly decreased when the PMNs stimulation is done in the presence of the extract at concentrations of 500, 250 and 125 g/ml. Moreover, the hydroxyl radical generation (OH.) is very much decreased at concentrations as low as 15.6 g Gbe/ml, which indicates that the extract also has free radical scavenging activity. Gbe is able at least to reduce very severel the activity of myeloperoxidase contained in neutrophils. This enzyme, secreted into the intra and extracellular medium, catalyzes the oxidation of chloride (Cl–) by H2O2 to yield strong oxidants (HOCl, chloramines) which are implicated in inflammatory processes 相似文献
2.
Pyrophosphate (PPi) is a non-hydrolyzable ATP analogue known to affect the binding between myosin heads and actin. By using a dynamic laser light scattering method, we have shown that 1–2 mM PPi enhances the increase in
values induced by Ca2+ in isolated thick myofilaments fromLimulus striated muscle. However, similar treatment has no effect on the
values of filaments suspended in either relaxing solution or ATP-free solution.
is the average linewidth of the photoelectron count autocorrelation function of the light scattered. PPi had no effect on the increase of
values by Sr2+ but it substantially increased the
values of the thick myofilaments suspended in Ba2+-substituted Ca2+ activating solution. The results show that PPi also affects the energy-requiring cyclic cross-bridge motions. 相似文献
3.
N-acyl dehydroalanines react with and scavenge mainly superoxide radical (O-2.) and hydroxyl radical (HO.). The ortho-methoxyphenylacetyl dehydroalanine derivative, indexed as AD-20, protects mice against damage resulting from total body X-irradiation, as measured by the increase in their survival time. AD-20 increases the LD50 at 30 days from 6.1 to 7.3 Gy in animals exposed to a wide range of X-rays (6 to 10 Gy). The dose reduction factor (D R F) of AD-20 is 1.20. We postulate that such radioprotective effect may result from its free radical scavenging activity. 相似文献
4.
Summary (3H)Nitrendipine binding to the bovine tracheal muscle membrane at 25°C was rapid, saturable (Bmax=14.8±3.9fmol/mg protein) and of high affinity (Kd=0.15±0.04 nM). The rank order of Ca2+ antagonists competing for airway (3H)nitrendipine binding was nitrendipine
nisoldipine
nifedipine » verapamil. Cromolyn, however, neither inhibited nor increased the binding.J.B.C. is a visiting associate professor at the NYMMC. We thank Ms. Pang-jang Chang for technical assistance. This work is supported by a grant (NSC 72-0412-BO10-R20) from the National Science Council, ROC. To whom reprint requests should be addressed: Allergic Disease Center, Creighton University School of Medicine, Omaha, Nebraska 68178. 相似文献
5.
Zhong Z Kotova O Davidescu A Ehrén I Ekberg K Jörnvall H Wahren J Chibalin AV 《Cellular and molecular life sciences : CMLS》2004,61(21):2782-2790
Proinsulin-connecting peptide (C-peptide) exerts physiological effects partially via stimulation of Na+, K+-ATPase. We determined the molecular mechanism by which C-peptide stimulates Na+, K+-ATPase in primary human renal tubular cells (HRTCs). Incubation of the cells with 5 nM human C-peptide at 37°C for 10 min stimulated 86Rb+ uptake by 40% (p<0.01). The carboxy-terminal pentapeptide was found to elicit 57% of the activity of the intact molecule. In parallel with ouabain-sensitive 86Rb+ uptake, C-peptide increased subunit phosphorylation and basolateral membrane (BLM) abundance of the Na+, K+-ATPase 1 and 1 subunits. The increase in BLM abundance of the Na+, K+-ATPase 1 and 1 subunits was accompanied by depletion of 1 and 1 subunits from the endosomal compartments. C-peptide action on Na+, K+-ATPase was ERK1/2-dependent in HRTCs. C-peptide-stimulated Na+, K+-ATPase activation, phosphorylation of 1-subunit and translocation of 1 and 1 subunits to the BLM were abolished by a MEK1/2 inhibitor (20 M PD98059). C-peptide stimulation of 86Rb+ uptake was also abolished by preincubation of HRTCs with an inhibitor of PKC (1 M GF109203X). C-peptide stimulated phosphorylation of human Na+, K+-ATPase subunit on Thr-Pro amino acid motifs, which form specific ERK substrates. In conclusion, C-peptide stimulates sodium pump activity via ERK1/2-induced phosphorylation of Thr residues on the subunit of Na+, K+-ATPase.Received 15 June 2004; received after revision 14 September 2004; accepted 14 September 2004 相似文献
6.
Summary The free energy of transfer ( G
t
0
) of KBrO3 and KIO3 from water to 10, 20 and 30% dioxane-water mixtures have been studied from conductometric measurements. The G
t
0
values are in the order of BrO
3
–
>IO
3
–
. 相似文献
7.
H. Kobayashi N. Morisaki Y. Tago Y. Hashimoto S. Iwasaki E. Kawachi R. Nagata K. Shudo 《Cellular and molecular life sciences : CMLS》1995,51(11):1081-1084
A major cytokinin found in coconut milk was isolted by using the tobacco callus growth-promoting assay as a guide during purification. The structure of the factor was determined to be 14-O-{3-O-[-d-galactopyranosyl-(12)--d--galactopyranosyl-(13)--L-arabinofuranosyl]-4-O-(-L-arabinofuranosyl)--d-galactopyranosyl}-trans-zeatin riboside [G3A2-ZR] by various NMR techniques, including heteronuclear multiple bond connectivity by 2D multiple quantum NMR (HMBC), as well as mass spectroscopy and sugar analysis. The optimum concentration of G3A2-ZR for cytokinin activity in the tobacco callus assay was estimated to be 5×10–6 M, so that G3A2-ZR is one order of magnitude more potent than 1,3-diphenylurea and one order less potent than zeatin riboside. At least 20% of the cytokinin activity of coconut milk could be attributed to G3A2-ZR. 相似文献
8.
Summary Cyclic voltammetry of molecular oxygen in aprotic media (dimethylformamide) and in the presence of bilirubin and other bile pigments shows that superoxide anion (
) undergoes proton-induced dismutation. Lactam hydrogens of bile pigments are sufficiently acid to induce
disproportionation to O2 and H2O2. Because of its characteristic lipophilic behavior, a biological role for natural bilirubin similar to that of other non-enzymatic lipophilic scavengers of
is suggested. 相似文献
9.
M. N. Schwarcz de Tarlovsky S. G. Goijman M. P. Molina Portela A. O. M. Stoppani 《Cellular and molecular life sciences : CMLS》1990,46(5):502-505
Several 4-(aminomethylisoxazolyl)-1,2-naphthoquinones inhibited growth and DNA synthesis inTrypanosoma cruzi and stimulated O2 uptake and
generation by the parasite epimastigotes and their mitochondrial and microsomal membranes; these results support the idea that oxygen radicals play a role in quinone toxicity. Maximal effects on respiration and
generation were observed with antimycin-inhibited cells. Similar results as well as stimulation of H2O2 production were obtained withCrithidia fasciculata despite the presence of catalase in this organism.Acknowledgments. This work was aided by grants from the University of Buenos Aires, the Scientific Office of the American States Organization and CEDIQUIFA (Buenos Aires). S.G.G. and M.P.M.P. are Research Fellows and A.O.M.S. is Career Investigator of CONICET (Argentina). L. T. Viñas and M. G. Gutierrez lent able technical assistance. 相似文献
10.
I. J. Miller N. K. McCallum C. M. Kirk B. M. Peake 《Cellular and molecular life sciences : CMLS》1982,38(2):230-231
Summary The free radical oxidation of 1 and 6-tetrahydrocannabinol has been examined by spin trapping techniques and intermediates that would lead to cannabinol have been trapped. The 1st step in the oxidation of 1-THC involves the removal of 3-H, while for 6-THC, either 2-H or 5-H. Intermediates were isolated which could be pyrolysed to the diene and cannabinol. 相似文献
11.
G. Meyer G. Bottà G. Fedele D. Cremaschi 《Cellular and molecular life sciences : CMLS》1995,51(11):1045-1051
In intact tissue, [d-Ala2,MePhe4, Gly-ol5] enkephalin (10–5 M;-ligand), diminsihed short-circuit current (Isc) and increased water, Na+ and Cl– net fluxes in vitro under open circuit conditions; it also inhibitedL-valine absorption andL-valine-dependent variations of short-circuit current (Isc, val). Naloxone (10–6 M) antagonized these effects. In the absence of the muscularis and myenteric plexus this enkephalin or morphine (-ligand) reduced Isc and Isc, val. These enkephalin effects occurred at different times. Different concentrations of enkephalin were tested for their effects on Isc, val. [d-Ala2,d-Leu5] enkephalin (mainly a -ligand) significantly decreased Isc but not Isc, val. The reduction ofL-valine absorption does not depend on the effects on basal ion transport. Interaction of opioids with-receptors located in the submucosal plexus and/or in the epithelial cell accounts for this reduction. This enkephalin effect seems to be at least partially under the control of the myenteric plexus. 相似文献
12.
Summary The differences in responses of Tb, Tf and
both to intrahypothalamic and i.v. administration of NA were measured both at noon and at midnight in the pigeon. Although the Tb and
were at a higher level in the daytime, no differences in the magnitude of the fall in
and Tb were obtained after either intrahypothalamic or i.v. injections of NA, whether it was measured during the day or at night. The only marked difference was the more prominent vasodilatation in the daytime after both routes of injection. 相似文献
13.
R. Walter G. Schaechtelin L. C. Craig 《Cellular and molecular life sciences : CMLS》1974,30(3):306-308
Zusammenfassung Der Effekt von Na+-, NH4
+- und Ca++-Ionen auf die Blutdruckaktivität von Arginin-Vasopressom wurde untersucht und mit analogen Experimenten (Val5-Angiotensin II-Asp1--Amid) verglichen. Die Wirkungsweise der Ionen-induzierten Potenzierung von Vasopressin wird diskutiert.
Supported by USPHS Grant No. AM-13567.
Abbreviations used are: AVP, arginine-vasopressin; bp, blood pres sure; U, unit;n, number of experiments; , mean value; S.E. standard error;p, level of significance; NS, not significant. 相似文献
Supported by USPHS Grant No. AM-13567.
Abbreviations used are: AVP, arginine-vasopressin; bp, blood pres sure; U, unit;n, number of experiments; , mean value; S.E. standard error;p, level of significance; NS, not significant. 相似文献
14.
J. Pincemail M. Dupuis C. Nasr P. Hans M. Haag-Berrurier R. Anton C. Deby 《Cellular and molecular life sciences : CMLS》1989,45(8):708-712
Summary
Ginkgo biloba extract is known to be efficient in diseases associated with free radical generation. The purpose of this work was to study, under in vitro conditions, the action ofGinkgo biloba extract (Gbe) against superoxide anion (
), which is directly or indirectly implicated in cell damage.Gbe appears to have both an
scavenging effect and also a superoxide dismutase activity. Its antiradical effect was demonstrated by low temperature electron spin resonance and in a non-enzymatic system (phenazine methosulfate-NADH), and its enzymatic activity was shown by polarographic determination. 相似文献
15.
S. S. Hillman 《Cellular and molecular life sciences : CMLS》1982,38(8):940-941
Summary Lymphatic injection of propranolol (0.2–10 g) into toads decreased exercise heart rate in a dose-dependent manner. There was a significant linear corrleation between exercise heart rate and maximal oxygen consumption rates
. These data are consistent with the hypothesis that blood oxygen transport is the limiting process for
max in anuran amphibians.This work was supported by a grant from the National Science Foundation (PCM-8021808). I am grateful to Dr P.C. Withers for logistical support and Dr S. Yokota for the initial idea. 相似文献
16.
Summary The crystal structure of chabazite was investigated by means of X-rays. A new (Si, Al)-lattice was found [different from that ofWyart (1933)] in the space group
: (Si, Al)=(12i)=x y z withx=0,104,y=0,333,z=–0,128. The lattice forms two kinds of cages: hexagonal prisms and big holes, which explain the sorptive properties of this zeolite.
Mitteilung Nr. 102, Abteilung für Kristallographie und Strukturlehre, Universität Bern. 相似文献
Mitteilung Nr. 102, Abteilung für Kristallographie und Strukturlehre, Universität Bern. 相似文献
17.
A. Lupulescu 《Cellular and molecular life sciences : CMLS》1980,36(2):246-247
Summary A marked uptake (9-fold) of the3H-PGF2 was found specifically over heterochromatin in the nuclei of neoplastic cells. Lower but significant uptakes of3H-PGF2 were also found in the nuclei of control epidermal cells, which indicate the presence of nuclear receptors in the epidermal neoplastic cells. 相似文献
18.
P. K. Ghosh O. W. Neuhaus N. M. Biswas 《Cellular and molecular life sciences : CMLS》1981,37(7):686-687
Summary The urinary protein
2u stimulates adrenal
5-3 dehydrogenase activity and prevents adrenal enlargement in estrogen-treated adult male rats.Acknowledgements. Dehydroepiandrosterone used in this study was donated by Organon(India) Ltd, Calcutta. This work received financial support from University Grants' Commission, New Delhi. The author's thanks are due to Prof. A. K. Maiti and Prof. C. Deb, Department of Physiology, Calcutta University, for their constant encouragement. 相似文献
19.
A2 adenosine receptors were characterized in human glomerular mesangial cells using [3H] 5-N-ethylcarboxamidoadenosine (NECA) as a tracer. There was a single group of receptor sites with a KD of 184 nM, and a number of sites of 317 fmol/mg of cell protein. Adenosine agonists increased 5-nucleotidase activity via A2 receptor stimulation. The specific A2 agonist-NECA, at 0.1 and 1 m, was a potent inhibitor of DNA synthesis. 相似文献
20.
E. Sümer A. Weiske G. Benckiser J. C. G. Ottow 《Cellular and molecular life sciences : CMLS》1995,51(4):419-422
Waste water purification is characterized by intensive mineralization and nitrification processes. Because of the high O2 demand, temporarily anaerobic conditions may be produced, and denitrification by nitrifying organisms as well as heterotropic denitrification may contribute to N2O release. In situ measurements (1993–1994) suggest that N2O is released from activated sludge in a domestic waste water treatment plant at an average rate of 1040 g m–2h–1 with a range between zero and 6198 g m–2h–1. The production of N2O seems to be related to the concentration of NO
2
–
and NO
3
–
as well as to the pH. In the waste water about 75–200 g N2O l–1 is dissolved. This N2O is released after discharge into the receiving waters. The N2O is produced essentially by nitrification rather than by heterotropic denitrification. On a long-term scale the increasing use of mechanical-biological waste water purification plants world-wide may add increasingly to the anthropogenic production of N2O, although the present amount of N2O produced is negligible compared to its global terrestrial production. 相似文献