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排序方式: 共有662条查询结果,搜索用时 15 毫秒
131.
High density lipoprotein modulates platelet function. 总被引:1,自引:0,他引:1
Stefan Barlage Dorothee Boettcher Alfred Boettcher Ashraf Dada Gerd Schmitz 《Cytometry. Part A》2006,69(3):196-199
BACKGROUND: Platelet activation by atherogenic lipoproteins can be antagonized by high density lipoprotein (HDL), probably via interaction with the ATP-binding cassette transporter A1 (ABCA1). METHODS: ABCA1 expression and its association with cholesterol rich membrane domains was analyzed by mRNA and Western blot analysis. HDL effects on platelet receptor clustering were analyzed by flow cytometric analysis of fluorescence resonance energy transfer between fluorochrome-labeled antibodies. RESULTS: ABCA1 expression increased upon megakaryocytic differentiation of human stem cells and ABCA1 protein partially associated to LubroIWX-resistant membrane domains. Plasma HDL-cholesterol in healthy donors negatively correlated to the platelet membrane cholesterol content. Receptor cluster analysis revealed a decrease in the association of Gplb and FcgammaRII upon incubation of platelets with HDL3. CONCLUSION: Our results suggest that HDL modulates platelet reactivity by altering lipid raft associated receptor clustering. 相似文献
132.
Jan N Hansen Fabian Kaiser Philipp Leyendecker Birthe Stüven JensHenning Krause Fatemeh Derakhshandeh Jaazba Irfan Tommy J Sroka Kenley M Preval Paurav B Desai Michael Kraut Heidi Theis AnnaDorothee Drews Elena DeDomenico Kristian Hndler Gregory J Pazour David J P Henderson David U Mick Dagmar Wachten 《EMBO reports》2022,23(8)
The primary cilium constitutes an organelle that orchestrates signal transduction independently from the cell body. Dysregulation of this intricate molecular architecture leads to severe human diseases, commonly referred to as ciliopathies. However, the molecular underpinnings how ciliary signaling orchestrates a specific cellular output remain elusive. By combining spatially resolved optogenetics with RNA sequencing and imaging, we reveal a novel cAMP signalosome that is functionally distinct from the cytoplasm. We identify the genes and pathways targeted by the ciliary cAMP signalosome and shed light on the underlying mechanisms and downstream signaling. We reveal that chronic stimulation of the ciliary cAMP signalosome transforms kidney epithelia from tubules into cysts. Counteracting this chronic cAMP elevation in the cilium by small molecules targeting activation of phosphodiesterase‐4 long isoforms inhibits cyst growth. Thereby, we identify a novel concept of how the primary cilium controls cellular functions and maintains tissue integrity in a specific and spatially distinct manner and reveal novel molecular components that might be involved in the development of one of the most common genetic diseases, polycystic kidney disease. 相似文献
133.
Nina Bednaršek Geraint A Tarling Dorothee CE Bakker Sophie Fielding Anne Cohen Alan Kuzirian Dan McCorkle Bertrand Lézé Roberto Montagna 《Global Change Biology》2012,18(7):2378-2388
Anthropogenic ocean acidification is likely to have negative effects on marine calcifying organisms, such as shelled pteropods, by promoting dissolution of aragonite shells. Study of shell dissolution requires an accurate and sensitive method for assessing shell damage. Shell dissolution was induced through incubations in CO2‐enriched seawater for 4 and 14 days. We describe a procedure that allows the level of dissolution to be assessed and classified into three main types: Type I with partial dissolution of the prismatic layer; Type II with exposure of underlying crossed‐lamellar layer, and Type III, where crossed‐lamellar layer shows signs of dissolution. Levels of dissolution showed a good correspondence to the incubation conditions, with the most severe damage found in specimens held for 14 days in undersaturated condition (Ω ~ 0.8). This methodology enables the response of small pelagic calcifiers to acidified conditions to be detected at an early stage, thus making pteropods a valuable bioindicator of future ocean acidification. 相似文献
134.
Atzler D Mieth M Maas R Böger RH Schwedhelm E 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(23):2294-2298
Nitric oxide (NO), the endogenous modulator of vascular tone and structure, originates from oxidation of L-arginine catalysed by NO synthase (NOS). The L-arginine derivative L-homoarginine serves as an alternative NOS substrate releasing NO, competing with L-arginine for NOS, arginase, and arginine transport. In the present article we report a liquid chromatography-tandem mass spectrometric (LC-tandem MS) method for the determination of L-homoarginine in human plasma by stable-isotope dilution. L-[(13)C(6)]-Homoarginine was used as internal standard. This method provides high sample throughput of 25-μl aliquots of plasma with an analysis time of 4 min using LC-tandem MS electrospray ionisation in the positive mode (ESI+). Specific transitions for L-homoarginine and L-[(13)C(6)]-homoarginine were m/z 245 → m/z 211 and m/z 251 → m/z 217, respectively. The mean intra- and interassay CVs were 7.4 ± 4.5% (±SD) for 0.1-50 μmol/L and 7.5 ± 2.0% for 2 and 5 μmol/L, respectively. Applying this method, a mean plasma concentration of L-homoarginine of 2.5 ± 1.0 μmol/L was determined in 136 healthy humans. 相似文献
135.
Weiling Wang Hao Xu Yang Shi Sandhya Nandedkar Hao Zhang Haiqing Gao Thom Feroah Dorothee Weihrauch Marie L. Schulte Deron W. Jones Jason Jarzembowski Mary Sorci-Thomas Kirkwood A. Pritchard Jr. 《Journal of lipid research》2010,51(9):2560-2570
The relationship between high-density lipoprotein and pulmonary function is unclear. To determine mechanistic relationships we investigated the effects of genetic deletion of apolipoprotein A-I (apoA-I) on plasma lipids, paraoxonase (PON1), pro-inflammatory HDL (p-HDL), vasodilatation, airway hyperresponsiveness and pulmonary oxidative stress, and inflammation. ApoA-I null (apoA-I−/−) mice had reduced total and HDL cholesterol but increased pro-inflammatory HDL compared with C57BL/6J mice. Although PON1 protein was increased in apoA-I−/− mice, PON1 activity was decreased. ApoA-I deficiency did not alter vasodilatation of facialis arteries, but it did alter relaxation responses of pulmonary arteries. Central airway resistance was unaltered. However, airway resistance mediated by tissue dampening and elastance were increased in apoA-I−/− mice, a finding also confirmed by positive end-expiratory pressure (PEEP) studies. Inflammatory cells, collagen deposition, 3-nitrotyrosine, and 4-hydroxy-2-nonenal were increased in apoA-I−/− lungs but not oxidized phospholipids. Colocalization of 4-hydroxy-2-nonenal with transforming growth factor β-1 (TGFβ-1 was increased in apoA-I−/− lungs. Xanthine oxidase, myeloperoxidase and endothelial nitric oxide synthase were increased in apoA-I−/− lungs. Dichlorodihydrofluorescein-detectable oxidants were increased in bronchoalveolar lavage fluid (BALF) in apoA-I−/− mice. In contrast, BALF nitrite+nitrate levels were decreased in apoA-I−/− mice. These data demonstrate that apoA-I plays important roles in limiting pulmonary inflammation and oxidative stress, which if not prevented, will decrease pulmonary artery vasodilatation and increase airway hyperresponsiveness. 相似文献
136.
Two new oribatid mite species of the genus Truncozetes (Oribatida, Epactozetidae), Truncozetes ecuadoriensis
sp. n. and Truncozetes monodactylus
sp. n., are described from the Ecuadorian soils. The morphology of the gnathosoma and the legs is presented in detail for the first time for the species of Truncozetes. An identification key to all known species of the family Epactozetidae is given. 相似文献
137.
MDHM, a macrophage-activating product of Mycoplasma fermentans, stimulates murine macrophages to synthesize nitric oxide and become tumoricidal 总被引:1,自引:0,他引:1
Dorothee Ruschmeyer Hansjörg Thude Peter F. Mühlradt 《FEMS immunology and medical microbiology》1993,7(3):223-230
Abstract In continuation of previous work on macrophage activation by a Mycoplasma fermentans -derived product, originally named “mycoplasma-derived high mol. wt. material” (MDHM), we have investigated whether MDHM was capable of inducing synthesis of the reactive nitrogen intermediate nitric oxide (NO), thus rendering macrophages cytocidal. Mycoplasmas were first delipidated with acetone, and MDHM activity was then extracted with 50 mM 1-O-octyl-β- d -glucopyranoside to yield a particularly active new preparation of MDHM which we have named MDHM-D (D for detergent). In combination with IFN-γ, MDHM-D activated macrophages to produce reactive nitrogen intermediates and kill P815 mastocytoma cells in co-culture. P815 target cells were chosen because they are TNF-resistant. Macrophages from the LPS-low responder strain C3H/HeJ were used to minimize interference from possible LPS contamination. MDHM-D activity in this system was strictly IFN-γ-dependent. In the presence of 25 U/ml IFN-γ MDHM-D gave a half maximal response at a dilution of 1/100 000, showing a parallel concentration dependency for nitrite production and cytocidal activity. 相似文献
138.
Racemic synthetic 3HC18 juvenile hormone, dissolved in paraffin oil, was injected into adult Locusta migratoria and the excreted radioactive material in the faeces was determined. Within 48 hr two-thirds of the injected radioactivity can be recovered in the frass, half of it within 3 hr. The remaining one-third of the injected label is incorporated or is released as water. Adult locusts of either sex or of different ages show no difference in the metabolic pathways of the JH and its excretion rate.The excreta contain as a degradation product 7-ethyl-3,11-dimethyl-cis-10,11-epoxy-trans, trans-2,6 trideca-dienoic acid, the corresponding dioldienoic acid and the dioldienoic methyl ester. Unchanged Cecropia JH was also found in the frass. The radioactive hormone, as well as the metabolites, were excreted mainly by the Malpighian tubules; smaller amounts of the radioactive material were also found in the fore-, mid, and hindgut. 相似文献
139.
140.
Markus Anton Michael Passreiter Dorothee Lay Thanh-Phuong Thai Karin Gorgas Wilhelm W. Just 《Cell biochemistry and biophysics》2000,32(1-3):27-36
The authors characterized on a molecular level the clofibrate-inducible 26-kDa integral peroxisomal membrane protein (Pmp26p,
Pex11-1p) of rat liver. By screening cDNA databases with the obtained Pex11-1p-cDNA, a second homologous cDNA was identified
that codes for a polypeptide with slightly larger molecular mass than Pex11-1p. The authors call this polypeptide Pex11-2p.
Studies on the topology of Pex11-1p revealed two transmembrane domains with the N- and C-terminus facing the cytoplasm. The
C-terminal tail of Pex11-1p ends in a consensus dilysine motif of the type-KXKXX-COOH, which is known to be involved in the
ADP-ribosylation factor (ARF)1-coat protein (COP) I coat (ARF)1-dependent membrane recruitment to Golgi membranes. Studies
with isolated peroxisomes incubated in the presence of cytosol, adenosine triphosphate and GTPγS, indeed, provided evidence
for specific binding of ARF and coatomer to peroxisomes. Expression of Pex11-1p in Chinese hamster ovary (CHO) wild-type cells
led to a twofold increase in the number of peroxisomes, but expression in a temperature-sensitive CHO mutant, defective in
coatomer, induced elongation and tubulation of peroxisomal structures, rather than numerical proliferation. The obtained results
for the first time offer a mechanism explaining Pex11-1p-, as well as ARF- and coatomer-mediated peroxisomal vesiculation.
Two models are presented that may explain how these observations fit in with peroxisome biogenesis. 相似文献