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排序方式: 共有946条查询结果,搜索用时 15 毫秒
941.
Background and purpose:
It is postulated that nitrite requires reduction to nitric oxide in order to exert its relaxant effect upon isolated hypoxic vessels. Herein, we evaluate the relative contribution of nitric oxide and characterize the downstream mechanisms of nitrite-induced vasorelaxation.Experimental approach:
Aortic rings were treated with pharmacological agents and exposed to hypoxia (<1% O2). Following pre-constriction, nitrite (10 µM final) was added to appropriate baths; isometric tension was recorded throughout.Key results:
Nitrite (under hypoxic conditions at physiological pH) is capable of exerting physiological effects that cannot be completely inhibited by the inhibitor of soluble guanylate cyclase (sGC), 1H [1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one or a nitric oxide scavenger (carboxy-2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide). Simultaneous blockade of both sGC and cyclooxygenase (COX) completely inhibited the response to nitrite. With regard to the nitric oxide-dependent component, we confirm that aldehyde oxidase, but not xanthine oxidase or endothelial nitric oxide synthase, was important for the actions of nitrite in our model.Conclusions and implications:
Nitric oxide generated from nitrite is not exclusively responsible for the physiological actions observed in isolated hypoxic vessels. Nitrite operates via different pathways dependent on the presence or absence of endothelium to produce vasorelaxation. In intact vessels, both sGC and COX enzymes appear to be important. Irrespective of this difference in relaxation mechanism, nitrite is capable of producing the same maximum relaxation, regardless of the presence of endothelium. Having investigated possible nitrite reduction sites, we confirm that aldehyde oxidase is important for the actions of nitrite. 相似文献942.
Idova GV Jur'ev DV Zhukova EN Kuznetsova SM 《Bulletin of experimental biology and medicine》2011,151(3):356-358
The development of a depression-like state in C57Bl/6J mice with repeated defeat experience (10 and 20 days) was accompanied by inhibition of the immune response (evaluated from the number of IgM antibody-producing cells). Activation of postsynaptic 5-HT(1A) receptors with a selective agonist 8-OH-DPAT (1.0 mg/kg) in these animals had no effect on the immune reaction. In mice without the experience of confrontations, stimulation of postsynaptic receptors caused a decrease in the number of IgM antibody-producing cells at the peak of the immune response induced by sheep erythrocytes (5×10(8) cells). However, the count of these cells remained unchanged in mice with a depression-like state (irrespective of the stage of disorder). Activation of presynaptic 5-HT(1A) receptors with 8-OH-DPAT (0.1 mg/kg) in control animals and mice with 10-day defeat experience was followed by immune stimulation. These changes were not observed in mice with a depression-like state caused by 20-day social stress. 相似文献
943.
Maegele M Lefering R Yucel N Tjardes T Rixen D Paffrath T Simanski C Neugebauer E Bouillon B;AG Polytrauma of the German Trauma Society 《Injury》2007,38(3):298-304
BACKGROUND: There is increasing evidence for acute traumatic coagulopathy occurring prior to emergency room (ER) admission but detailed information is lacking. PATIENTS AND METHODS: A retrospective analysis using the German Trauma Registry database including 17,200 multiple injured patients was conducted to determine (a) to what extent clinically relevant coagulopathy has already been established upon ER admission, and whether its presence was associated (b) with the amount of intravenous fluids (i.v.) administered pre-clinically, (c) with the magnitude of injury, and (d) with impaired outcome and mortality. Eight thousand seven hundred and twenty-four patients with complete data sets were screened. RESULTS: Coagulopathy upon ER admission as defined by prothrombin time test (Quick's value) <70% and/or platelets <100,000 microl(-1), was present in 34.2% of all patients. There was an increasing incidence for coagulopathy with increasing amounts of i.v. fluids administered pre-clinically. Coagulopathy was observed in >40% of patients with >2000 ml, in >50% with >3000 ml, and in >70% with >4000 ml administered. Ten percentage of patients presented with clotting disorders although pre-clinical resuscitation was limited to 500 ml of i.v. fluids maximum. The mean ISS score in the coagulopathy group was 30 (S.D. 15) versus 21 (S.D. 12) (p<0.001). Twenty-nine percentage of patients with coagulopathy developed multi organ failure (p<0.001). Early in-hospital mortality (<24h) was 13% in patients with coagulopathy (p<0.001) and overall in-hospital mortality totalled 28% (p<0.001). CONCLUSION: There is a high frequency of established coagulopathy in multiple injury upon ER admission. The presence of early traumatic coagulopathy was associated with the amount of intravenous fluids administered pre-clinically, magnitude of injury, and impaired outcome. 相似文献
944.
The composition of erythrocytic lipids was studied in patients with chronic nonobstructive bronchitis in the phase of clinical remission concurrent with urolithiasis. There was a significant increase in the proportion of phosphatidylserine with the decreased levels of sphingomyelin and phosphatidylcholine, a reduction in the relative quantity of fatty acids of iso- and anteisometric structure, an impairment in the relations between fatty acids that are precursors of the synthesis of eicosanoids of different series, as well as a decrease in the total unsaturation of erythrocytic lipids. The impairments found in the composition of erythrocytic lipids are markers of membrane destruction and they may serve as diagnostic criteria for concomitant pulmonary and renal lesions. 相似文献
945.
Embryo morphology or cleavage stage: how to select the best embryos for transfer after in-vitro fertilization 总被引:11,自引:15,他引:11
Ziebe S; Petersen K; Lindenberg S; Andersen AG; Gabrielsen A; Andersen AN 《Human reproduction (Oxford, England)》1997,12(7):1545-1549
This retrospective study of 1001 in-vitro fertilization (IVF) cycles
included a consecutive series of single transfers (n = 341), dual transfers
(n = 410) and triple transfers (n = 250) where all the transferred embryos
in each cycle were of identical quality score and identical cleavage stage.
In our 2 day culture system, transfer of 4- cell embryos resulted in a
significantly higher implantation rate and pregnancy rate (23 and 49%)
compared with 2-cell embryos (12 and 22%) and 3-cell embryos (7 and 15%).
Furthermore, the transfer of 4-cell embryos resulted in a significantly
higher pregnancy rate compared with embryos that had cleaved beyond the
4-cell stage (28%). The implantation rate (21%) and pregnancy rate (43%)
after transfer of embryos of score 1.0 were significantly higher than after
transfer of embryos of score 2.0 (14 and 32% respectively). Transferring
embryos of score 2.1 resulted in significantly higher implantation rates
(26%) and similar pregnancy rates compared with score 1.0. Transferring
embryos of score 2.2-3.0 resulted in a significantly lower implantation
rate (5%) and pregnancy rate (15%). A striking finding was that embryos of
quality score 2.0 had a significantly lower implantation rate compared with
embryos of quality score 1.0 and 2.1 and a significantly lower pregnancy
rate compared to embryos of quality score 1.0. We also found a lower
implantation rate and pregnancy rate when transferring 3-cell embryos.
These findings may indicate periods of increased sensitivity to damage
during the cell cycle. In conclusion, these results substantiate the idea
of the superiority of 4-cell embryos and demonstrate that minor amounts of
fragments in the embryo may not be of any importance. These findings may
call for a shift when weighing the two main morphological components
(quality score and cleavage stage) in the sense that reaching a 4-cell
cleavage stage even with the presence of a minor amount of fragments should
be preferred to a 2-cell embryo with no fragments.
相似文献
946.
Sorokina IV Tolstikova TG Zhukova NA Petrenko NI Uzenkova NV Shul'ts EE Popova NA 《Bulletin of experimental biology and medicine》2006,142(1):69-72
We studied the effects of four synthetic amides of betulonic acid containing amino acid fragments (d,l-α-alanine, β-alanine, and their methyl esters) on the rate of growth and metastatic dissemination of transplantable Lewis
lung carcinoma in C57Bl/6 mice. The test compounds were administered intragastrically in a single dose of 500 mg/kg. 3-[-oxo-20(29)-lupen-28-oilamino]-propionic
acid suppressed primary tumor growth (by 26%) and decreased the number of lung metastases (by more than 2 times). Antitumor
and antimetastatic activity of triterpenoids decreased after methylation of the amino acid fragment in betulonic acid.
__________
Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 7, pp. 78–81, July, 2006 相似文献