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21.
In the human erythrocyte membrane phosphatidylcholine and sphingomyelin reside mainly in the outer leaflet, whereas the aminophospholipids, phosphatidylethanolamine and phosphatidylserine, are mainly found in the inner leaflet. Maintenance of phospholipid asymmetry has been assumed to involve interactions between the aminophospholipids and the membrane skeleton, in particular spectrin. To investigate whether spectrin contributes to maintaining the phospholipid transbilayer distribution and kinetics of redistribution, we studied erythrocytes from hereditary spherocytosis patients whose spectrin levels ranged from 34% to 82% of normal. The phospholipid composition and the accessibility of membrane phospholipids to hydrolysis by phospholipases were in the normal range. Spin-labeled phosphatidylserine and phosphatidylethanolamine analogues that had been introduced into the outer leaflet were rapidly transported at 37 degrees C to the inner leaflet, whereas the redistribution of spin-labeled phosphatidylcholine was slower. The kinetics of transbilayer movement of these spin-labeled phospholipid in all samples was in the normal range and was not affected by the level of spectrin. Although these erythrocyte membranes contained as little as 34% of the normal level of spectrin and were characterized by several physical abnormalities, the composition, distribution, and transbilayer kinetics of the phospholipids were found to be normal. We therefore conclude that spectrin plays, at best, only a minor role in maintaining the distribution of erythrocyte membrane phospholipid. 相似文献
22.
Styles LA; Schalkwijk CG; Aarsman AJ; Vichinsky EP; Lubin BH; Kuypers FA 《Blood》1996,87(6):2573-2578
Acute chest syndrome (ACS) is associated with significant morbidity and is the leading cause of death in patients with sickle cell disease (SCD). Recent reports suggest that bone marrow fat embolism can be detected in many cases of severe ACS. Secretory phospholipase A2 (sPLA2) is an important inflammatory mediator and liberates free fatty acids, which are felt to be responsible for the acute lung injury of the fat embolism syndrome. We measured SPLA2 levels in 35 SCD patients during 20 admissions for ACS, 10 admissions for vaso-occlusive crisis, and during 12 clinic visits when patients were at the steady state. Eleven non-SCD patients with pneumonia were also evaluated. To determine if there was a relationship between sPLA2 and the severity of ACS we correlated SPLA2 levels with the clinical course of the patient. In comparison with normal controls (mean = 3.1 +/- 1.1 ng/mL), the non- SCD patients with pneumonia (mean = 68.6 +/- 82.9 ng/mL) and all three SCD patient groups had an elevation of SPLA2 (steady state mean = 10.0 +/- 8.4 ng/mL; vaso-occlusive crisis mean = 23.7 +/- 40.5 ng/mL; ACS mean = 336 +/- 209 ng/mL). In patients with ACS sPLA2 levels were 100- fold greater than normal control values, 35 times greater than values in SCD patients at baseline, and five times greater than non-SCD patients with pneumonia. The degree of SPLA2 elevation in ACS correlated with three different measures of clinical severity and, in patients followed sequentially, the rise in SPLA2 coincided with the onset of ACS. The dramatic elevation of SPLA2 in patients with ACS but not in patients with vaso-occlusive crisis or non-SCD patients with pneumonia and the correlation between levels of SPLA2 and clinical severity suggest a role for SPLA2 in the diagnosis and, perhaps, in the pathophysiology of patients with ACS. 相似文献
23.
该研究以山东万杰医学院为例,针对目前招生规模越来越大,生源质量不断下滑,大面积学生逃学、厌学、考试成绩不及格的严峻现实,提出有关教学方法、教学内容和考核方式的教学三项改革,这三项改革举措顺应了当前高校教育(特别是民办高校教育)形势的发展趋势。通过改革实践,已初见成效,进一步验证了只有坚定不移地搞好教学三项改革,才能保证和提高教学质量,从而使广大学生及其家长的利益得到充分保障;也只有大张旗鼓地继续搞好教学三项改革,学校才有生存和可持续发展的空间。 相似文献
24.
Diane Purper-Ouakil Hilario Blasco-Fontecilla Tomas Ros Eric Acquaviva Tobias Banaschewski Sarah Baumeister Elisa Bousquet Aurore Bussalb Marie Delhaye Richard Delorme Renate Drechsler Allison Goujon Alexander Häge Anna Kaiser Louis Mayaud Konstantin Mechler Caroline Menache Olivier Revol Friederike Tagwerker Susanne Walitza Anna Maria Werling Stephanie Bioulac Daniel Brandeis 《Journal of child psychology and psychiatry, and allied disciplines》2022,63(2):187-198
25.
Mayo Weiss Ruediger G.H. Baumeister Andreas Frick Jens Wallmichrath Peter Bartenstein Axel Rominger 《Korean journal of radiology》2015,16(1):188-195
ObjectiveThe aim of this prospective study was to determine whether the additional use of the single photon emission computed tomography/CT (SPECT/CT) technique improves the diagnostic value of planar lymphoscintigraphy in patients presenting with primary lymph edema of the lower limb.ResultsIn comparison to pathological planar scintigraphic findings, the addition of SPECT/CT provided relevant additional information regarding the presence of dermal backflow (86%), the anatomical extent of lymphatic disorders (64%), the presence or absence of lymph nodes (46%), and the visualization of lymph vessels (4%).ConclusionAs an adjunct to planar lymphoscintigraphy, SPECT/CT specifies the anatomical correlation of lymphatic disorders and thus improves assessment of the extent of pathology due to the particular advantages of tomographic separation of overlapping sources. The interpretation of scintigraphic data benefits not only in baseline diagnosis, but also in physiotherapeutical and microsurgical treatments of primary lymphedema. 相似文献
26.
The proteasomal subunit Rpn6 is a molecular clamp holding the core and regulatory subcomplexes together 总被引:2,自引:0,他引:2
Pathare GR Nagy I Bohn S Unverdorben P Hubert A Körner R Nickell S Lasker K Sali A Tamura T Nishioka T Förster F Baumeister W Bracher A 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(1):149-154
Proteasomes execute the degradation of most cellular proteins. Although the 20S core particle (CP) has been studied in great detail, the structure of the 19S regulatory particle (RP), which prepares ubiquitylated substrates for degradation, has remained elusive. Here, we report the crystal structure of one of the RP subunits, Rpn6, and we describe its integration into the cryo-EM density map of the 26S holocomplex at 9.1?? resolution. Rpn6 consists of an α-solenoid-like fold and a proteasome COP9/signalosome eIF3 (PCI) module in a right-handed suprahelical configuration. Highly conserved surface areas of Rpn6 interact with the conserved surfaces of the Pre8 (alpha2) and Rpt6 subunits from the alpha and ATPase rings, respectively. The structure suggests that Rpn6 has a pivotal role in stabilizing the otherwise weak interaction between the CP and the RP. 相似文献
27.
Human erythrocytes have a low basal permeability to L-glutamate and are not known to have a functional glutamate transporter. Here, treatment of human erythrocytes with arsenite was shown to induce the uptake of L-glutamate and D-aspartate, but not that of D-glutamate or L-alanine. The majority of the arsenite-induced L-glutamate influx was via a high-affinity, Na(+)-dependent system showing characteristics of members of the "excitatory amino acid transporter" (EAAT) family. Western blots and immunofluorescence assays revealed the presence of a member of this family, EAAT3, on the erythrocyte membrane. Erythrocytes infected with the malaria parasite Plasmodium falciparum take up glutamate from the extracellular environment. Although the majority of uptake is via a low-affinity Na(+)-independent pathway there is, in addition, a high-affinity uptake component, raising the possibility that the parasite activates the host cell glutamate transporter. 相似文献
28.
29.
Ittermann T Baumeister SE Völzke H Wasner C Schminke U Wallaschofski H Nauck M Lüdemann J 《Clinical endocrinology》2012,76(4):526-532
Objective Oxidized LDL (oxLDL) is involved in the pathogenesis of atherosclerosis. Thus, it is important to investigate putative risk factors for increased oxLDL. Evidence suggests that, compared to euthyroid individuals, LDL‐cholesterol (LDL‐C) levels are lower in individuals with overt hyperthyroidism. Whereas oxidization of LDL‐C into oxLDL is increased in overt hyper‐ and hypothyroidism, it has not been investigated whether subclinical thyroid dysfunction impacts on oxLDL levels in general. We have analysed the association between serum thyrotrophin (TSH) levels and oxLDL in a population‐based study. Design, Patients and Measurements Of the 4308 individuals enrolled in the Study of Health in Pomerania, data from 3519 individuals were analysed (680 missing the oxLDL variable). oxLDL was measured by the oxLDL competitive ELISA on a BEP 2000. Multivariable linear regression models were performed to assess the association between serum TSH and oxLDL levels. Results TSH was positively associated with oxLDL in a curvilinear fashion with increasing serum TSH levels. Subgroup analyses revealed a significant association only in the group of individuals >60 years. Additionally, serum TSH levels were not associated with the ratio of oxLDL to LDL (β = ?0·04; 95% CI = ?0·08, 0·01; P = 0·084). Conclusions We demonstrate an association between serum TSH and oxLDL levels especially in the range of subclinical thyroid disease. Our study suggests that serum TSH levels affect LDL‐C production or clearance rather than the LDL‐C oxidation processes. 相似文献
30.
BO Motayo PA Akinduti FA Adeyakinu PO Okerentugba JC Nwanze CC Onoh HC Innocent-Adiele IO Okonko 《African health sciences》2013,13(4):1091-1097