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排序方式: 共有234条查询结果,搜索用时 15 毫秒
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Grellier P Blum J Santana J Bylèn E Mouray E Sinou V Teixeira AR Schrével J 《Molecular and biochemical parasitology》1999,98(2):239-252
Differentiation of the non-dividing trypomastigote form of Trypanosoma cruzi, the causative agent of Chagas disease, to the dividing amastigote form normally occurs in cytoplasm of infected cells. Here we show that calyculin A. a potent inhibitor of protein phosphatases 1 and 2A, induces at pH 7.5 extracellular transformation of long slender trypomastigotes to round amastigote-like forms which acquire characteristic features observed after the normal differentiation process: repositioning and structural changes of the kinetoplast, release of surface neuraminidase, and expression of amastigote-specific epitopes. Calyculin A inhibits parasite phosphatases and changes in the phosphorylation of specific proteins occur during the transformation process. As an exposure of trypomastigotes to calyculin A concentrations as low as 1 nM and for only 1-2 h is sufficient to induce transformation, the inhibition of calyculin A-sensitive phosphatase(s) appears to play a major role in initiating the trypomastigote differentiation. 相似文献
3.
Tiia Keklinen Martina Luchetti Damaris Aschwanden Angelina R. Sutin Antonio Terracciano 《European journal of ageing》2022,19(4):1529
This study aimed to investigate associations between individual-level (personality traits, quality of life) and country-level (gross domestic product per capita, number of policies and action plans for physical activity) factors with self-reported and accelerometer-based physical activity and cross-level interactions among European countries. Based on the Survey of Health, Ageing and Retirement in Europe (SHARE) from 2019–2020, self-reported physical activity (N = 46,617 from 27 countries) and accelerometer-based average acceleration and intensity gradient (N = 855 from 10 countries) were analyzed. Mixed-model regressions with two levels (individuals nested within countries) were used for analyses. Between countries differences accounted for relatively small portions of the variability in self-reported physical activity (intraclass correlation, ICC = 7.5%), average acceleration (ICC = 3.5%), and intensity gradient (ICC = 1.9%). There were more associations between individual- and country-level factors and self-reported physical activity than with accelerometer-based physical activity. The association between individual-level variables and accelerometer-based physical activity did not differ between countries. Cross-level interactions suggested that associations between some personality traits and self-reported physical activity were stronger in countries with lower GDP. Both individual- and country-level factors are related to participation in more intensive physical activities. Adults with less resilient personality traits living in countries with lower resources are at the highest risk for physical inactivity. Supplementary InformationThe online version contains supplementary material available at 10.1007/s10433-022-00737-8. 相似文献
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Tamme T Leibur E Kulla A 《Stomatologija / issued by public institution "Odontologijos studija" ... [et al.]》2007,9(2):61-64
We report the case of a 22-year-old woman who is suspected of having primary Sj?gren s syndrome. She complaining of bilateral swelling of eyelids and the parotid glands of three weeks duration. Physical examination revealed a bilateral enlargement of both parotid glands, which were solid and painful. Sj?gren s syndrome was suspected at that stage, and the serologic and specific analysis were done. All these tests didn t find any autoimmune or visceral features typical of Sj?gren s syndrome and autoantibodies were negative. During follow-up time the right facial nerve palsy developed. Pulmonary radiography revealed bihilar lymphadenopathy and labial salivary gland biopsy revealed non-caseating granuloma. The patient was classified as having stage I sarcoidosis. This case demonstrates the importance of being aware of the leading clinical signs and symptoms in case of Heerfordt syndrome. 相似文献
6.
Enn K Seppet Margus Eimre Tiia Anmann Evelin Seppet Nadezhda Peet Tuuli Kmbre Kalju Paju Andres Piirsoo Andrei V Kuznetsov Marko Vendelin Frank N Gellerich Stephan Zierz Valdur A Saks 《Experimental & Clinical Cardiology》2005,10(3):173-183
BACKGROUND:
The present review examines the role of intra-cellular compartmentation of energy metabolism in vivo.OBJECTIVE:
To compare the kinetics of the activation of mitochondrial respiration in skinned cardiac fibres by exogenous and endogenous adenine nucleotides in dependence of the modulation of cellular structure and contraction.METHODS:
Saponin-permeabilized cardiac fibres or cells were analyzed using oxygraphy and confocal microscopy.RESULTS:
Mitochondria respiration in fibres or cells was upregulated by cumulative additions of ADP to the medium with an apparent Km of 200 μM to 300 μM. When respiration was stimulated by endogenous ADP produced by intracellular ATPases, a near maximum respiration rate was achieved at an ADP concentration of less than 20 μM in the medium. A powerful ADP-consuming system, consisting of pyruvate kinase and phosphoenolpyruvate, that totally suppressed the activation of respiration by exogenous ADP, failed to abolish the stimulation of respiration by endogenous ADP, but did inhibit respiration after the cells were treated with trypsin. The addition of up to 4 μM of free Ca2+ to the actively respiring fibres resulted in reversible hypercontraction associated with a decreased apparent Km for exogenous ADP. These changes were fully abolished in fibres after the removal of myosin by KCl treatment.CONCLUSIONS:
Mitochondria and ATPases, together with cytoskeletal proteins that establish the structural links between mitochondria and sarcomeres, form complexes – intracellular energetic units (ICEUs) – in cardiac cells. Within the ICEUs, the mitochondria and ATPases interact via specialized energy transfer systems, such as the creatine kinase- and adenylate kinase-phosphotransfer networks, and direct ATP channelling. Disintegration of the structure and function of ICEUs results in dyscompartmentation of adenine nucleotides and may represent a basis for cardiac diseases. 相似文献7.
From an ethanol extract of the stems of Burasa?a madagascarensis Thouars (Menispermaceae) were isolated N-acetylnornuciferine and two clerodane-type diterpenes, one of them, epicordatine, being new. The structures were established by the interpretation of the spectral data. All the described compounds exhibited weak antimalarial activity. 相似文献
8.
Long-term outcome of patients with claudication after balloon angioplasty of the femoropopliteal arteries 总被引:6,自引:0,他引:6
PURPOSE: To report the long-term outcome of patients with lifestyle-limiting claudication after percutaneous transluminal angioplasty (PTA) of the femoropopliteal arteries. MATERIALS AND METHODS: Between 1989 and 1992, 173 consecutive claudicant patients (mean age, 65 years; age range, 41-90 years) underwent PTA in 218 limbs; all interventions included femoral and/or popliteal arterial segments, and additional iliac (n = 27) and infrapopliteal (n = 11) arterial lesions were also treated. Patients were followed up for 7-10 years. Altogether, 37 (17%) limbs were classified as Fontaine class 2A, and 181 (83%) were class 2B. Average length of the primary lesion was 5.2 cm. Reinterventions were analyzed. Patency rates and patient survival were assessed by means of life table analysis. Cox-Mantel tests and Cox proportional hazards models were used to define associated independent determinants. Development of chronic critical ischemia (CCI) and its determinants was assessed by using the Pearson chi(2) test and multiple logistic regression analysis. RESULTS: The primary and secondary patencies (+/- standard error of the estimate), respectively, were 46% +/- 3 and 63% +/- 3 at 1 year, 25% +/- 3 and 41% +/- 4 at 5 years, and 14% +/- 3 and 22% +/- 4 at 10 years. One-third (71 of 218) of the limbs required repeat interventions, including surgical revascularization in 35 limbs. Fourteen (6.4%) limbs developed CCI, resulting in a 0.8% incidence per year. In multivariate analysis, poor postinterventional peripheral runoff was an indicator of increased risk of CCI development (P =.03). CONCLUSION: Although the long-term patency rates of PTA of the femoropopliteal arteries in claudicant patients were poor, the acceptable number of reinterventions and the low frequency of development of CCI imply the long-term benefits achievable with this treatment. 相似文献
9.
Arzel E Rocca P Grellier P Labaeïd M Frappier F Guéritte F Gaspard C Marsais F Godard A Quéguiner G 《Journal of medicinal chemistry》2001,44(6):949-960
The paper describes, in its first part, a new synthesis of benzo-delta-carbolines, cryptolepines, and their salts. The strategy is based on the association between halogen-dance and hetero-ring cross-coupling. It is fully convergent and regioselective with interesting overall yields from 27% to 70%. A halogen-dance mechanism in quinoline series is also proposed. The formal synthesis of potential antimalarial compounds and the first total synthesis of 11-isopropylcryptolepine are also described. In the second part, cytotoxic activity against mammalian cells and activities against Plasmodium falciparum and Trypanosoma cruzi of benzo-delta-carbolines and delta-carbolines were evaluated in vitro to study the structure-activity relationships. For benzo-delta-carbolines, methylation at N-5 increases the cytotoxic and antiparasitic activities. A further alkylation on C-11 generally increases the cytotoxic activity but not the antiparasitic activity, cryptolepine and 11-methylcryptolepine being the most active on both parasites. Taking advantage of the fluorescence of the indoloquinoline chromophore, cryptolepine was localized by fluorescence microscopy in parasite DNA-containing structures suggesting that these compounds act through interaction with parasite DNA as proposed for cryptolepine on melanoma cells. For delta-carbolines, methylation at N-1 is essential for the antimalarial activity. 1-Methyl-delta-carboline specifically accumulates in the intracellular parasite. It has weak cytotoxic activity and can be considered as a potential antimalarial compound. 相似文献
10.
Girault S Delarue S Grellier P Berecibar A Maes L Quirijnen L Lemiere P Debreu-Fontaine MA Sergheraert C 《The Journal of pharmacy and pharmacology》2001,53(7):935-938
In the fight against malaria, chemotherapy using bisacridines may represent an alternative method to overcoming chloroquine-resistance. Eight bis(9-amino-6-chloro-2-methoxyacridines), in which acridine moieties were linked by polyamines substituted with a side chain, were tested for their in-vivo activity upon mice infected by Plasmodium berghei. Three of the compounds revealed antimalarial activity but no relationship could be deduced from a comparison of in-vitro and in-vivo activities. N-alkylation of the central amino group generated toxicity and, therefore, only compounds N-acylated in this position can be selected as leads. 相似文献