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排序方式: 共有212条查询结果,搜索用时 15 毫秒
51.
52.
Bilirubin, a major intravascular product of heme catabolism, is a potent antioxidant compound. Numerous studies have been published showing the relationship between serum bilirubin levels and atherosclerosis. In the present investigation all the epidemiological studies available on the effect of serum bilirubin levels and atherosclerotic disease were analyzed. Studies on the epidemiology of atherosclerotic diseases in relation to serum bilirubin levels were searched in the MEDLINE database. Selected studies were subdivided according to serum bilirubin levels and severity of atherosclerotic disease. Because of the limited number of females involved in the studies, only males were included into meta-analysis. Associations for ordered categorical variables (bilirubin and natural history of graded atherosclerosis) were assessed to find correlation and linear trend between analyzed variables. A stratified analysis was conducted to compare risks of clinical outcomes. Eleven relevant studies were used for analysis. A close negative relationship was found between serum bilirubin levels and severity of atherosclerosis (Spearman rank coefficient r = -0.31,P < 0.0001). The linear trend was confirmed in analysis of proportions with x(2) values for both disease conditions to be very significant (P < 0.0001). Unambiguous inverse relationship between serum bilirubin levels and atherosclerosis was demonstrated in this preliminary meta-analytic study. These results indicate the importance of hem oxygenase-related products in the prevention of oxidative stress-mediated diseases. 相似文献
53.
Effects of methoprene and 20-hydroxyecdysone on the development and hemagglutination activity (HA) were studied in both sexes of two members of the Culex pipiens complex-anautogenous C. p. quinquefasciatus and autogenous C. p. molestus. Juvenile hormone analogue (methoprene) and 20-hydroxyecdysone caused developmental changes in both mosquito strains. High larval mortality, prolongation of intermolt period in each larval instar and in the pupal stage, and morphological changes in the larval-pupal and pupal-adult transformations were also observed. Developmental changes were accompanied with some differences in the HA. HA was found in both sexes of both experimental mosquito strains. The juvenile hormone analogue used in the larval stage caused significant decrease of HA in the gut of adults of both sexes. On the other hand, 20-hydroxyecdysone decreased HA only in the female gut. Results obtained indicate that HA depends on the sex, the studied organ, and the level of hormones. 相似文献
54.
Jaran Apold Hans G. Eiken Elisabeth Svensson Erich Kunert Libor Kozak Petr Cechak Flemming Güttler Jacques Giltay Uta Lichter-Konecki Dominique Melle Jadwiga Maria Jaruzelska 《Human genetics》1993,92(2):107-109
We have compiled data on the frequencies of the phenylketonuria G272X mutation in European populations. This mutation occurs north of the Alps. It has a particularly high frequency in the Oslo Fjord region of Norway with the adjacent Bohuslän region of Sweden. An intermediate frequency was noted in a separate area, the eastern part of Germany with the adjacent western part of Czechoslovakia. The G272X mutation was associated with phenylalanine hydroxylase haplotype 7, except for one case with haplotype 3. Genealogical studies going back eight to nine generations revealed no common source for this mutation, but there was some geographical convergence to the Bohuslän region. These findings suggest a single origin for this mutation, with at least one founding population in south-eastern Norway/adjacent Sweden. 相似文献
55.
Stanislav Obruca Sinisa Petrik Pavla Benesova Zdenek Svoboda Libor Eremka Ivana Marova 《Applied microbiology and biotechnology》2014,98(13):5883-5890
Spent coffee grounds (SCG), an important waste product of the coffee industry, contain approximately 15 wt% of coffee oil. The aim of this work was to investigate the utilization of oil extracted from SCG as a substrate for the production of poly(3-hydroxybutyrate) (PHB) by Cupriavidus necator H16. When compared to other waste/inexpensive oils, the utilization of coffee oil resulted in the highest biomass as well as PHB yields. Since the correlation of PHB yields and the acid value of oil indicated a positive effect of the presence of free fatty acids in oil on PHB production (correlation coefficient R 2?=?0.9058), superior properties of coffee oil can be probably attributed to the high content of free fatty acids which can be simply utilized by the bacteria culture. Employing the fed-batch mode of cultivation, the PHB yields, the PHB content in biomass, the volumetric productivity, and the Y P/S yield coefficient reached 49.4 g/l, 89.1 wt%, 1.33 g/(l h), and 0.82 g per g of oil, respectively. SCG are annually produced worldwide in extensive amounts and are disposed as solid waste. Hence, the utilization of coffee oil extracted from SCG is likely to improve significantly the economic aspects of PHB production. Moreover, since oil extraction decreased the calorific value of SCG by only about 9 % (from 19.61 to 17.86 MJ/kg), residual SCG after oil extraction can be used as fuel to at least partially cover heat and energy demands of fermentation, which should even improve the economic feasibility of the process. 相似文献
56.
57.
Libor Zvorka Rmy Lassus John Robert Britton Julien Cucherousset 《Global Change Biology》2020,26(10):5693-5704
Reducing the abundances of invasive species by removals aims to minimize their ecological impacts and enable ecosystem recovery. Removal methods are usually selective, modifying phenotypic traits in the managed populations. However, there is little empirical evidence of how removal‐driven changes in multiple phenotypic traits of surviving individuals of invasive species can affect ecosystem functioning and recovery. Overcoming this knowledge gap is highly relevant because individuals are the elemental units of ecological processes and so integrating individual‐level responses into the management of biological invasions could improve their efficiency. Here we provide novel demonstration that removals by trapping, angling and biocontrol from lakes of the globally invasive crayfish Procambarus clarkii induced substantial changes in multiple phenotypic traits. A mesocosm experiment then revealed that these changes in phenotypic traits constrain recovery of basic ecosystem functions (decomposition of organic matter, benthic primary production) by acting in the opposite direction than the effects of reduced invader abundance. However, only minor ecological impacts of invader abundance and phenotypic traits variation remained a year after its complete eradication. Our study provides quantitative evidence to an original idea that removal‐driven trait changes can dampen recovery of invaded ecosystems even when the abundance of invasive species is substantially reduced. We suggest that the phenotypic responses of invaders to the removal programme have strong effects on ecosystem recovery and should be considered within the management of biological invasions, particularly when complete eradication is not achievable. 相似文献
58.
Dzirbíková Z Kiss A Okuliarová M Kopkan L Cervenka L 《Cellular and molecular neurobiology》2011,31(2):225-232
Hypertensive rats with multiple extra copies of the renin gene (TGR) exert an inverted circadian blood pressure (BP) profile.
We investigated whether circadian oscillations in the hypothalamic suprachiasmatic nucleus (SCN), a main circadian oscillator,
and the paraventricular nucleus (PVN), involved in BP control, are influenced in TGR rats. The expression of the clock gene
per1, a marker of circadian timing, was measured in the SCN and PVN. Moreover, the expression of genes encoding vasopressin (AVP),
vasoactive intestinal peptide (VIP) in the SCN, and AVP and oxytocin (OXT) in the PVN were studied by in situ hybridization.
Expression of the per1 gene showed a distinct circadian rhythm in both the SCN and PVN with no differences observed between the TGR and control
Sprague–Dawley (SD) rats. The expression of avp in the SCN was rhythmic in both strains and moderately higher in TGR than in SD rats while no significant changes were found
in the PVN. The expression of vip in the SCN and oxt in the PVN did not differ between both strains. Our results may indicate that changes occurring downstream to the SCN are
responsible for the development of the inverted BP rhythm in TGR hypertensive rats. 相似文献
59.
Nováček J Zawadzka-Kazimierczuk A Papoušková V Zídek L Sanderová H Krásný L Koźmiński W Sklenář V 《Journal of biomolecular NMR》2011,50(1):1-11
Two novel 5D NMR experiments (CACONCACO, NCOCANCO) for backbone assignment of disordered proteins are presented. The pulse
sequences exploit relaxation properties of the unstructured proteins and combine the advantages of 13C-direct detection, non-uniform sampling, and longitudinal relaxation optimization to maximize the achievable resolution and
minimize the experimental time. The pulse sequences were successfully tested on the sample of partially disordered delta subunit
from RNA polymerase from Bacillus subtilis. The unstructured part of this 20 kDa protein consists of 81 amino acids with frequent sequential repeats. A collection of
0.0003% of the data needed for a conventional experiment with linear sampling was sufficient to perform an unambiguous assignment
of the disordered part of the protein from a single 5D spectrum. 相似文献
60.
Statin treatment increases formation of carbon monoxide and bilirubin in mice: a novel mechanism of in vivo antioxidant protection 总被引:1,自引:0,他引:1
Muchova L Wong RJ Hsu M Morioka I Vitek L Zelenka J Schröder H Stevenson DK 《Canadian journal of physiology and pharmacology》2007,85(8):800-810
Heme oxygenase (HO) has a central role in cellular antioxidant defences and vascular protection, and it may mediate pleiotropic actions of drugs used in cardiovascular therapy. We investigated whether long-term use of statins upregulates HO activity and increases carbon monoxide (CO) and bilirubin levels in vivo. Adult FvB mice were given atorvastatin or rosuvastatin (5 mg/kg) daily by i.p. injections for 1, 2, or 3 weeks. HO activity, tissue CO, bilirubin, and antioxidant levels, total plasma bilirubin, and carboxyhemoglobin (COHb) were measured. Fold changes in heart HO activity significantly increased after 1, 2, and 3 weeks of atorvastatin (1.24 +/- 0.06 (p < or = 0.05); 1.29 +/- 0.26 (p < or = 0.03); 1.33 +/- 0.08 (p < 0.01), respectively) and 2 and 3 weeks of rosuvastatin (1.23 +/- 0.20 (p < or = 0.03); 1.63 +/- 0.42 (p < 0.01), respectively). Heart tissue CO and COHb levels also increased after 3 weeks with atorvastatin (1.30 +/- 0.24 (p < or = 0.05); 1.92 +/- 0.17 (p < or = 0.001), respectively) and rosuvastatin (1.47 +/- 0.13 (p < or = 0.004); 1.63 +/- 0.12 (p < or = 0.001), respectively). Significant increases in heart antioxidant levels were observed after statin treatment and corroborated by heart bilirubin content elevations. Antioxidant level increases were abolished by treatment with an HO inhibitor. These findings suggest that the induction of HO and the production of its products, CO and bilirubin, may be a mechanism by which statins exert antioxidant actions and confer cardioprotection in vivo. 相似文献