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111.
Lips KS Lührmann A Tschernig T Stoeger T Alessandrini F Grau V Haberberger RV Koepsell H Pabst R Kummer W 《Life sciences》2007,80(24-25):2263-2269
Acetylcholine (ACh), derived both from nerve fibres and from non-neuronal sources such as epithelial cells, is a major regulator of airway function. There is evidence that dysfunction of the neuronal cholinergic system is involved in the pathogenesis of asthma. Here, we asked whether the pulmonary non-neuronal ACh-synthesis and release machinery is altered in a rat and a mouse model of allergic airway disease. Animals were sensitized against ovalbumin, challenged by allergen inhalation, and sacrificed 24 or 48 h later. Targets of investigation were the high-affinity choline transporter-1 (CHT1), that mediates cellular uptake of choline, the ACh-synthesizing enzyme choline acetyltransferase (ChAT), the vesicular ACh transporter (VAChT), and the polyspecific organic cation transporters (OCT1-3), which are able to translocate choline and ACh across the plasma membrane. With cell-type specific distribution patterns, immunohistochemistry identified these proteins in airway epithelial cells and alveolar macrophages. Real-time RT-PCR revealed significant decreases in ChAT-, CHT1-, VAChT-, OCT-mRNA in the lung of sensitized and allergen challenged animals. These data were supported by immunohistochemistry, demonstrating reduced labeling intensity of airway epithelial cells. ChAT-, CHT1-, VAChT-, and OCT1-mRNA were also significantly reduced in cells recovered by bronchoalveolar lavage from sensitized and challenged rats. In conclusion, the pulmonary non-neuronal cholinergic system is down-regulated in acute allergic airway inflammation. In view of the role of ACh in maintenance of cell-cell-contacts, stimulation of fluid-secretion and of ciliary beat frequency, this down-regulation may contribute to epithelial shedding and ciliated cell dysfunction that occur in this pathological condition. 相似文献
112.
113.
13th Workshop consensus for vitamin D nutritional guidelines 总被引:1,自引:0,他引:1
Norman AW Bouillon R Whiting SJ Vieth R Lips P 《The Journal of steroid biochemistry and molecular biology》2007,103(3-5):204-205
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116.
Graziella V. DiRenzo Tate S. Tunstall Roberto Ibáñez Maya S. deVries Ana V. Longo Kelly R. Zamudio Karen R. Lips 《EcoHealth》2018,15(4):815-826
Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which has led to devastating declines in amphibian populations worldwide. Current theory predicts that Bd infections are maintained through both reproduction on the host’s skin and reinfection from sources outside of the host. To investigate the importance of external reinfection on pathogen burden, we infected captive-bred individuals of the highly susceptible Panamanian Golden Frog, Atelopus glyphus, and wild-caught glass frogs, Espadarana prosoblepon, with Bd. We housed the animals in one of three treatments: individually, in heterospecific pairs, and in conspecific pairs. For 8 weeks, we measured the Bd load and shedding rate of all frogs. We found that Atelopus had high rates of increase in both Bd load and shedding rate, but pathogen growth rates did not differ among treatments. The infection intensity of Espadarana co-housed with Atelopus was indistinguishable from those housed singly and those in conspecific pairs, despite being exposed to a large external source of Bd zoospores. Our results indicate that Bd load in both species is driven by pathogen replication within an individual, with reinfection from outside the host contributing little to the amplification of host fungal load. 相似文献
117.
K. van der Meijden N. Bravenboer N.F. Dirks A.C. Heijboer M. den Heijer G.M.J. de Wit C. Offringa P. Lips R.T. Jaspers 《Journal of cellular physiology》2016,231(11):2517-2528
An adequate vitamin D status is essential to optimize muscle strength. However, whether vitamin D directly reduces muscle fiber atrophy or stimulates muscle fiber hypertrophy remains subject of debate. A mechanism that may affect the role of vitamin D in the regulation of muscle fiber size is the local conversion of 25(OH)D to 1,25(OH)2D by 1α‐hydroxylase. Therefore, we investigated in a murine C2C12 myoblast culture whether both 1,25(OH)2D3 and 25(OH)D3 affect myoblast proliferation, differentiation, and myotube size and whether these cells are able to metabolize 25(OH)D3 and 1,25(OH)2D3. We show that myoblasts not only responded to 1,25(OH)2D3, but also to the precursor 25(OH)D3 by increasing their VDR mRNA expression and reducing their proliferation. In differentiating myoblasts and myotubes 1,25(OH)2D3 as well as 25(OH)D3 stimulated VDR mRNA expression and in myotubes 1,25(OH)2D3 also stimulated MHC mRNA expression. However, this occurred without notable effects on myotube size. Moreover, no effects on the Akt/mTOR signaling pathway as well as MyoD and myogenin mRNA levels were observed. Interestingly, both myoblasts and myotubes expressed CYP27B1 and CYP24 mRNA which are required for vitamin D3 metabolism. Although 1α‐hydroxylase activity could not be shown in myotubes, after treatment with 1,25(OH)2D3 or 25(OH)D3 myotubes showed strongly elevated CYP24 mRNA levels compared to untreated cells. Moreover, myotubes were able to convert 25(OH)D3 to 24R,25(OH)2D3 which may play a role in myoblast proliferation and differentiation. These data suggest that skeletal muscle is not only a direct target for vitamin D3 metabolites, but is also able to metabolize 25(OH)D3 and 1,25(OH)2D3. J. Cell. Physiol. 231: 2517–2528, 2016. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. 相似文献
118.
M Jongen W J van der Vijgh J C Netelenbos G J Postma P Lips 《Hormones et métabolisme》1989,21(10):577-580
Pharmacokinetic properties of pharmacological doses of 24,25-dihydroxyvitamin-D3 [24,25(OH)2D3] were determined in healthy volunteers. Four male subjects received 25 micrograms of 24,25(OH)2D3 as an intravenous bolus injection. Plasma concentrations of 24,25(OH)2D3, 25-hydroxyvitamin D and 1,25-dihydroxy-vitamin D were monitored during 14 days. In addition, serum ionized calcium, total calcium, inorganic phosphate, albumin, creatinine and intact hPTH(1-84) were measured during 14 days. The concentration-time curve of 24,25(OH)2D3 could be described by a two-exponential curve with half-lives of 3.0 +/- 0.9 hrs and 8.2 +/- 2.9 days (mean +/- SD). The volume of distribution was 0.19 +/- 0.02 liters/kg. None of the mentioned biochemical parameters, except serum 24,25(OH)2D3, changed markedly. In 18 subjects suffering from primary hyperparathyroidism, taking 25 micrograms of 24,25(OH)2D3 daily during three months, an average plateau level of 39 +/- 12 nmol/l of serum was observed. Bioavailability as estimated from this plateau level was approximately 70%. 相似文献
119.
Nitrogen concentration, ammonium/nitrate ratio and NaCl interaction in vegetative and reproductive growth of peanuts 总被引:1,自引:0,他引:1
Peanuts ( Arachis hypogaea L. cv. Shulamit) grown with NO3 − and saline water in hydroponics responded positively to addition of nitrogen (N) in their vegetative growth, but not in desert dune sand. In order to clarify these conflicting results, peanut plants were grown in a greenhouse pot experiment with fine calcareous sand. The nutrient solution contained 0 or 50 m M NaCl and 2 or 6 m M N in the form of Ca(NO3 )2 , NH4 NO3 or (NH4 )2 SO4 . Three replicates were harvested after 48 days (beginning of reproductive stage) and three after 109 days (pod filling). In addition, gynophores were treated with 0, 50, 100, 150 or 200 m M NaCl outside the growth pot to check their sensitivity to salt. Shoot dry weight became greater with increasing NH4 + /NO3 − ratio. Increasing the N concentration from 2 to 6 m M did not change shoot dry weight of the NH4 NO3 or NH4 + -fed plants, but caused a reduction in shoot dry weight of NO3 − -fed plants. Shoot dry weight was not affected by increasing the NaCl concentration to 50 m M . Salt caused an increase in the number of gynophores per plant and a reduction of the mean pod weight. A NaCl concentration of 100 m M and above reduced gynophore vitality. It is concluded that the salt sensitivity of peanut plants resides mainly in the sensitivity of the reproductive organs. 相似文献
120.
David Mills Ines M. M. Soares Cristopher F. Cresswell Herman S. Lips 《Physiologia plantarum》1984,61(1):149-154
Nitrate disappearance in tomato ( (ycopersicon esculentum Mill. cv. Azes) leaf sections kept under a stream of gas (nitrogen or air) has been studied, using leaf sections from plants supplied with low (7.5 mM) or high (17.5 mM) nitrate levels in their nutrient solution. Cessation of nitrate loss occurred in leaf sections taken from plants irrigated with low (7.5 mM) nitrate-containing nutrient solution. Resumption of nitrate disappearance occurred upon addition of exogenous nitrate by vacuum infiltration to leaf sections, suggesting that cessation of nitrate loss was due to exhaustion of the metabolic pool. We estimated that 53% of the total nitrate in leaf sections from low nitrate plants was located in a storage pool, probably the vacuole. The remainder was located in a pool, readily available for reduction (the metabolic pool). This pool is composed of nitrate in the free space as well as in the cytoplasm which was estimated to contain about 20% of the total nitrate.
Either under air or nitrogen, less nitrite was accumulated than nitrate assimilated suggesting that nitrite accumulation was not an adequate parameter for the estimation of nitrate utilization. Anaerobic conditions inhibited nitrite reduction whereas nitrate assimilation was not blocked. Nitrate loss from endogenous pool in leaf sections placed under aerobic conditions is suggested as an adequate method for the estimation of the metabolic pool of nitrate. 相似文献
Either under air or nitrogen, less nitrite was accumulated than nitrate assimilated suggesting that nitrite accumulation was not an adequate parameter for the estimation of nitrate utilization. Anaerobic conditions inhibited nitrite reduction whereas nitrate assimilation was not blocked. Nitrate loss from endogenous pool in leaf sections placed under aerobic conditions is suggested as an adequate method for the estimation of the metabolic pool of nitrate. 相似文献