Quantitative assessment of the contribution of sodium-dependent taurocholate co-transporting polypeptide (NTCP) to the hepatic uptake of rosuvastatin, pitavastatin and fluvastatin.

PubMed

Bi, Yi-an; Qiu, Xi; Rotter, Charles J; Kimoto, Emi; Piotrowski, Mary; Varma, Manthena V; Ei-Kattan, Ayman F; Lai, Yurong

2013-11-01

Hepatic uptake transport is often the rate-determining step in the systemic clearance of drugs. The ability to predict uptake clearance and to determine the contribution of individual transporters to overall hepatic uptake is therefore critical in assessing the potential pharmacokinetic and pharmacodynamic variability associated with drug-drug interactions and pharmacogenetics. The present study revisited the interaction of statin drugs, including pitavastatin, fluvastatin and rosuvastatin, with the sodium-dependent taurocholate co-transporting polypeptide (NTCP) using gene transfected cell models. In addition, the uptake clearance and the contribution of NTCP to the overall hepatic uptake were assessed using in vitro hepatocyte models. Then NTCP protein expression was measured by a targeted proteomics transporter quantification method to confirm the presence and stability of NTCP expression in suspended and cultured hepatocyte models. It was concluded that NTCP-mediated uptake contributed significantly to active hepatic uptake in hepatocyte models for all three statins. However, the contribution of NTCP-mediated uptake to the overall active hepatic uptake was compound-dependent and varied from about 24% to 45%. Understanding the contribution of individual transporter proteins to the overall hepatic uptake and its functional variability when other active hepatic uptake pathways are interrupted could improve the current prediction practice used to assess the pharmacokinetic variability due to drug-drug interactions, pharmacogenetics and physiopathological conditions in humans. Copyright © 2013 John Wiley & Sons, Ltd.

Calcium uptake in aquatic insects: influences of phylogeny and metals (Cd and Zn).

PubMed

Poteat, Monica D; Buchwalter, David B

2014-04-01

Calcium sequestration in the hypo-osmotic freshwater environment is imperative in maintaining calcium homeostasis in freshwater aquatic organisms. This uptake process is reported to have the unintended consequence of potentially toxic heavy metal (Cd, Zn) uptake in a variety of aquatic species. However, calcium uptake remains poorly understood in aquatic insects, the dominant invertebrate faunal group in most freshwater ecosystems. Here, we examined Ca uptake and interactions with heavy metals (Cd, Zn) at low ambient Ca levels (12.5 μmol l(-1)) in 12 aquatic insect species within Ephemerellidae (mayfly) and Hydropsychidae (caddisfly), two families differentially responsive to trace metal pollution. We found Ca uptake varied 70-fold across the 12 species studied. Body mass and clade (family) were found to significantly influence both Ca uptake and adsorption (P≤0.05). Zn and Cd uptake rate constants (ku) exhibited a strong correlation (r=0.96, P<0.0001), suggesting a shared transport system. Ca uptake failed to significantly correlate with either Zn or Cd ku values. Further, neither Zn nor Cd exhibited inhibitory effects toward Ca uptake. In fact, we saw evidence of modest stimulation of Ca uptake rates in some metal treatments. This work suggests that insects generally differ from other freshwater taxa in that aqueous Ca uptake does not appear to be compromised by Cd or Zn exposure. It is important to understand the trace metal and major ion physiology of aquatic insects because of their ecological importance and widespread use as ecological indicators.

Impact of ocean phytoplankton diversity on phosphate uptake

PubMed Central

Lomas, Michael W.; Bonachela, Juan A.; Levin, Simon A.; Martiny, Adam C.

2014-01-01

We have a limited understanding of the consequences of variations in microbial biodiversity on ocean ecosystem functioning and global biogeochemical cycles. A core process is macronutrient uptake by microorganisms, as the uptake of nutrients controls ocean CO2 fixation rates in many regions. Here, we ask whether variations in ocean phytoplankton biodiversity lead to novel functional relationships between environmental variability and phosphate (Pi) uptake. We analyzed Pi uptake capabilities and cellular allocations among phytoplankton groups and the whole community throughout the extremely Pi-depleted western North Atlantic Ocean. Pi uptake capabilities of individual populations were well described by a classic uptake function but displayed adaptive differences in uptake capabilities that depend on cell size and nutrient availability. Using an eco-evolutionary model as well as observations of in situ uptake across the region, we confirmed that differences among populations lead to previously uncharacterized relationships between ambient Pi concentrations and uptake. Supported by novel theory, this work provides a robust empirical basis for describing and understanding assimilation of limiting nutrients in the oceans. Thus, it demonstrates that microbial biodiversity, beyond cell size, is important for understanding the global cycling of nutrients. PMID:25422472

Nicotine transport in lung and non-lung epithelial cells.

PubMed

Takano, Mikihisa; Kamei, Hidetaka; Nagahiro, Machi; Kawami, Masashi; Yumoto, Ryoko

2017-11-01

Nicotine is rapidly absorbed from the lung alveoli into systemic circulation during cigarette smoking. However, mechanism underlying nicotine transport in alveolar epithelial cells is not well understood to date. In the present study, we characterized nicotine uptake in lung epithelial cell lines A549 and NCI-H441 and in non-lung epithelial cell lines HepG2 and MCF-7. Characteristics of [ 3 H]nicotine uptake was studied using these cell lines. Nicotine uptake in A549 cells occurred in a time- and temperature-dependent manner and showed saturation kinetics, with a Km value of 0.31mM. Treatment with some organic cations such as diphenhydramine and pyrilamine inhibited nicotine uptake, whereas treatment with organic cations such as carnitine and tetraethylammonium did not affect nicotine uptake. Extracellular pH markedly affected nicotine uptake, with high nicotine uptake being observed at high pH up to 11.0. Modulation of intracellular pH with ammonium chloride also affected nicotine uptake. Treatment with valinomycin, a potassium ionophore, did not significantly affect nicotine uptake, indicating that nicotine uptake is an electroneutral process. For comparison, we assessed the characteristics of nicotine uptake in another lung epithelial cell line NCI-H441 and in non-lung epithelial cell lines HepG2 and MCF-7. Interestingly, these cell lines showed similar characteristics of nicotine uptake with respect to pH dependency and inhibition by various organic cations. The present findings suggest that a similar or the same pH-dependent transport system is involved in nicotine uptake in these cell lines. A novel molecular mechanism of nicotine transport is proposed. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantitative single-photon emission computed tomography/computed tomography for technetium pertechnetate thyroid uptake measurement

PubMed Central

Lee, Hyunjong; Kim, Ji Hyun; Kang, Yeon-koo; Moon, Jae Hoon; So, Young; Lee, Won Woo

2016-01-01

Abstract Objectives: Technetium pertechnetate (99mTcO4) is a radioactive tracer used to assess thyroid function by thyroid uptake system (TUS). However, the TUS often fails to deliver accurate measurements of the percent of thyroid uptake (%thyroid uptake) of 99mTcO4. Here, we investigated the usefulness of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) after injection of 99mTcO4 in detecting thyroid function abnormalities. Materials and methods: We retrospectively reviewed data from 50 patients (male:female = 15:35; age, 46.2 ± 16.3 years; 17 Graves disease, 13 thyroiditis, and 20 euthyroid). All patients underwent 99mTcO4 quantitative SPECT/CT (185 MBq = 5 mCi), which yielded %thyroid uptake and standardized uptake value (SUV). Twenty-one (10 Graves disease and 11 thyroiditis) of the 50 patients also underwent conventional %thyroid uptake measurements using a TUS. Results: Quantitative SPECT/CT parameters (%thyroid uptake, SUVmean, and SUVmax) were the highest in Graves disease, second highest in euthyroid, and lowest in thyroiditis (P < 0.0001, Kruskal–Wallis test). TUS significantly overestimated the %thyroid uptake compared with SPECT/CT (P < 0.0001, paired t test) because other 99mTcO4 sources in addition to thyroid, such as salivary glands and saliva, contributed to the %thyroid uptake result by TUS, whereas %thyroid uptake, SUVmean and SUVmax from the SPECT/CT were associated with the functional status of thyroid. Conclusions: Quantitative SPECT/CT is more accurate than conventional TUS for measuring 99mTcO4 %thyroid uptake. Quantitative measurements using SPECT/CT may facilitate more accurate assessment of thyroid tracer uptake. PMID:27399139

Characterization of Transporters in the Hepatic Uptake of TAK-475 M-I, a Squalene Synthase Inhibitor, in Rats and Humans.

PubMed

Ebihara, T; Takeuchi, T; Moriya, Y; Tagawa, Y; Kondo, T; Moriwaki, T; Asahi, S

2016-06-01

TAK-475 (lapaquistat acetate) is a squalene synthase inhibitor and M-I is a pharmacologically active metabolite of TAK-475. Preclinical pharmacokinetic studies have demonstrated that most of the dosed TAK-475 was hydrolyzed to M-I during the absorption process and the concentrations of M-I in the liver, the main organ of cholesterol biosynthesis, were much higher than those in the plasma after oral administration to rats. In the present study, the mechanism of the hepatic uptake of M-I was investigated.The uptake studies of (14)C-labeled M-I into rat and human hepatocytes indicated that the uptakes of M-I were concentrative, temperature-dependent and saturable in both species with Km values of 4.7 and 2.8 μmol/L, respectively. M-I uptake was also inhibited by cyclosporin A, an inhibitor for hepatic uptake transporters including organic anion transporting polypeptide (OATP). In the human hepatocytes, M-I uptake was hardly inhibited by estrone 3-sulfate as an inhibitor for OATP1B1, and most of the M-I uptake was Na(+)-independent. Uptake studies using human transporter-expressing cells revealed the saturable uptake of M-I for OATP1B3 with a Km of 2.13 μmol/L. No obvious uptake of M-I was observed in the OATP1B1-expressing cells.These results indicated that M-I was taken up into hepatocytes via transporters in both rats and humans. OATP1B3 would be mainly involved in the hepatic uptake of M-I in humans. These findings suggested that hepatic uptake transporters might contribute to the liver-selective inhibition of cholesterol synthesis by TAK-475. This is the first to clarify a carrier-mediated hepatic uptake mechanism for squalene synthase inhibitors. © Georg Thieme Verlag KG Stuttgart · New York.

Specific stimulated uptake of acetylcholine by Torpedo electric organ synaptic vesicles.

PubMed Central

Parsons, S M; Koenigsberger, R

1980-01-01

The specificity of acetylcholine uptake by synaptic vesicles isolated from the electric organ of Torpedo californica was studied. In the absence of cofactors, [3H]acetylcholine was taken up identically to[14C]choline in the same solution (passive uptake), and the equilibrium concentration achieved inside the vesicles was equal to the concentration outside. In the presence of MgATP, [3H]acetylcholine and [14C]choline in the same solution were taken up identically, except only about half as much of each was taken up (suppressed uptake). [3H]Acetylcholine uptake was stimulated by MgATP and HCO3- about 4-fold relative to suppressed uptake, for a net concentrative uptake of about 2:1 (stimulated uptake). Uptake of [14C]choline in the same solution remained at the suppressed level. [3H]Acetylcholine taken up under stimulated conditions migrated with vesicles containing [14C]mannitol on analytical glycerol density gradients during centrifugation. Vesicle were treated with nine protein modification reagents under mild conditions. Two reagents had no effect on, dithiothreitol potentiated, and six reagents strongly inhibited subsequent stimulated uptake of [3H]acetylcholine. The results indicate that uptake of acetylcholine is conditionally specific for the transported substrate, is carried out by the synaptic vesicles rather than a contaminant of the preparation, and requires a functional protein system containing a critical sulfhydryl group. PMID:6934549

Coupling of methylmercury uptake with respiration and water pumping in freshwater tilapia Oreochromis niloticus.

PubMed

Wang, Rui; Wong, Ming-Hung; Wang, Wen-Xiong

2011-09-01

The relationships among the uptake of toxic methylmercury (MeHg) and two important fish physiological processes-respiration and water pumping--in the Nile tilapia (Oreochromis niloticus) were explored in the present study. Coupled radiotracer and respirometric techniques were applied to measure simultaneously the uptake rates of MeHg, water, and oxygen under various environmental conditions (temperature, dissolved oxygen level, and water flow). A higher temperature enhanced MeHg influx and the oxygen consumption rate but had no effect on the water uptake, indicating the influence of metabolism on MeHg uptake. The fish showed a high tolerance to hypoxia, and the oxygen consumption rate was not affected until the dissolved oxygen concentration decreased to extremely low levels (below 1 mg/L). The MeHg and water uptake rates increased simultaneously as the dissolved oxygen level decreased, suggesting the coupling of water flux and MeHg uptake. The influence of fish swimming performance on MeHg uptake was also investigated for the first time. Rapidly swimming fish showed significantly higher uptake rates of MeHg, water, and oxygen, confirming the coupling relationships among respiration, water pumping, and metal uptake. Moreover, these results support that MeHg uptake is a rate-limiting process involving energy. Our study demonstrates the importance of physiological processes in understanding mercury bioaccumulation in fluctuating aquatic environments. Copyright © 2011 SETAC.

Uptake and translocation of imidacloprid, clothianidin and flupyradifurone in seed-treated soybeans.

PubMed

Stamm, Mitchell D; Heng-Moss, Tiffany M; Baxendale, Frederick P; Siegfried, Blair D; Blankenship, Erin E; Nauen, Ralf

2016-06-01

Seed treatment insecticides have become a popular management option for early-season insect control. This study investigated the total uptake and translocation of seed-applied [(14) C]imidacloprid, [(14) C]clothianidin and [(14) C]flupyradifurone into different plant parts in three soybean vegetative stages (VC, V1 and V2). The effects of soil moisture stress on insecticide uptake and translocation were also assessed among treatments. We hypothesized that (1) uptake and translocation would be different among the insecticides owing to differences in water solubility, and (2) moisture stress would increase insecticide uptake and translocation. Uptake and translocation did not follow a clear trend in the three vegetative stages. Initially, flupyradifurone uptake was greater than clothianidin uptake in VC soybeans. In V1 soybeans, differences in uptake among the three insecticides were not apparent and unaffected by soil moisture stress. Clothianidin was negatively affected by soil moisture stress in V2 soybeans, while imidacloprid and flupyradifurone were unaffected. Specifically, soil moisture stress had a positive effect on the distribution of flupyradifurone in leaves. This was not observed with the neonicotinoids. This study enhances our understanding of the uptake and distribution of insecticides used as seed treatments in soybean. The uptake and translocation of these insecticides differed in response to soil moisture stress. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Mechanism of Aluminum Inhibition of Net 45Ca2+ Uptake by Amaranthus Protoplasts 1

PubMed Central

Rengel, Zdenko; Elliott, Daphne C.

1992-01-01

Calcium ions serve as a second messenger in signal transduction and metabolic regulation. Effects of Al on calcium homeostasis remain to be elucidated. Short-term net 45Ca2+ uptake by Amaranthus tricolor protoplasts was monitored from uptake media prepared to test the influence of pH, Al, and various inhibitors. Accumulation of 45Ca2+ increased during the first 3 to 6 minutes and then leveled off or declined. Al and Ca2+ channel blockers (verapamil and bepridil) decreased net 45Ca2+ uptake. This decrease was more pronounced when Al and bepridil were both present in uptake media, but Al did not aggravate verapamil-induced reduction of net 45Ca2+ uptake. Erythrosin B and calmidazolium each increased net 45Ca2+ uptake, probably by interfering with Ca2+ efflux. This effect was undetectable in the presence of Al. Mycophenolic acid decreased net 45Ca2+ uptake; guanosine alleviated this effect. Al-induced reduction of net 45Ca2+ uptake was not aggravated by mycophenolic acid. Net 45Ca2+ uptake was generally less at pH 4.5 than at 5.5 for all treatments. It is concluded that Al ions affect net 45Ca2+ uptake by binding to the verapamil-specific channel site that is different from the bepridil-specific one, as well as by interfering with the action of guanosine 5′-triphosphate-binding proteins. PMID:16668688

Glucose oxidation positively regulates glucose uptake and improves cardiac function recovery after myocardial reperfusion.

PubMed

Li, Tingting; Xu, Jie; Qin, Xinghua; Hou, Zuoxu; Guo, Yongzheng; Liu, Zhenhua; Wu, Jianjiang; Zheng, Hong; Zhang, Xing; Gao, Feng

2017-11-01

Myocardial reperfusion decreases glucose oxidation and uncouples glucose oxidation from glycolysis. Therapies that increase glucose oxidation lessen myocardial ischemia-reperfusion (I/R) injury. However, the regulation of glucose uptake during reperfusion remains poorly understood. We found that glucose uptake was remarkably diminished in the myocardium following reperfusion in Sprague-Dawley rats as detected by 18 F-labeled and fluorescent-labeled glucose analogs, even though GLUT1 was upregulated by threefold and GLUT4 translocation remained unchanged compared with those of sham-treated rats. The decreased glucose uptake was accompanied by suppressed glucose oxidation. Interestingly, stimulating glucose oxidation by inhibition of pyruvate dehydrogenase kinase 4 (PDK4), a rate-limiting enzyme for glucose oxidation, increased glucose uptake and alleviated I/R injury. In vitro data in neonatal myocytes showed that PDK4 overexpression decreased glucose uptake, whereas its knockdown increased glucose uptake, suggesting that PDK4 has a role in regulating glucose uptake. Moreover, inhibition of PDK4 increased myocardial glucose uptake with concomitant enhancement of cardiac insulin sensitivity following myocardial I/R. These results showed that the suppressed glucose oxidation mediated by PDK4 contributes to the reduced glucose uptake in the myocardium following reperfusion, and enhancement of glucose uptake exerts cardioprotection. The findings suggest that stimulating glucose oxidation via PDK4 could be an efficient approach to improve recovery from myocardial I/R injury. Copyright © 2017 the American Physiological Society.

Glutamine, glutamate, and other possible regulators of alpha-ketoglutarate and malate uptake by synaptic terminals.

PubMed

Shank, R P; Campbell, G L

1984-04-01

The uptake of alpha-ketoglutarate and malate by rat brain synaptosomal preparations was found to be affected by a variety of substances at physiologically relevant concentrations. Glutamine altered the uptake of alpha-ketoglutarate by causing an apparent reduction in the substrate-carrier affinity and an increase in Vmax. In contrast, glutamine did not appear to affect the Vmax of malate uptake, but it did increase markedly the uptake velocity at low concentrations of malate. L-Glutamate and L-aspartate were comparatively strong inhibitors of alpha-ketoglutarate and malate uptake. N-Acetylaspartate was a weak inhibitor of alpha-ketoglutarate uptake, a finding that contrasts with our previous observation that this compound potently inhibited alpha-ketoglutarate uptake by synaptosomes obtained from the cerebellum of 8- to 14-day-old mice. Ca2+ exhibited a variable effect but usually enhanced the uptake of alpha-ketoglutarate. The addition of small amounts of postmicrosomal supernatant to the incubation medium enhanced the uptake of alpha-ketoglutarate by low-density synaptosomes. By comparison, the uptake of glutamate, glutamine, gamma-aminobutyric acid, and several other amino acids was not affected. The enhancement of alpha-ketoglutarate uptake by the supernatant was due to a heat labile substance that was retained by dialysis tubing (MW cutoff = 8,000) and Amicon filter cones (CF 25), and was precipitated by ammonium sulfate at 60% saturation. In experiments in which the metabolic conversion of [U-14C] alpha-ketoglutarate to glutamate, aspartate, glutamine, and gamma-aminobutyric acid was determined, the presence of glutamine and glutamate in the incubation medium did not affect the pattern of labelling appreciably.

Long term trend and interannual variability of land carbon uptake — the attribution and processes

NASA Astrophysics Data System (ADS)

Fu, Zheng

2017-04-01

Ecosystem carbon (C) uptake in terrestrial ecosystems has increased over the past five decades, but with large interannual variability (IAV). However, we are not clear on the attribution and the processes that control the long-term trend and IAV of land C uptake. Using atmospheric inversion net ecosystem exchange (NEE) data, we quantified the trend and IAV of NEE across the globe, the Northern Hemisphere (NH), and the Southern Hemisphere (SH), and decomposed NEE into carbon uptake amplitude and duration during each year from 1979-2013. We found the NH rather than the SH determined the IAV, while both hemispheres contributed equivalently to the global NEE trend. Different ecosystems in the NH and SH had differential relative contributions to their trend and IAV. The long-term trends of increased C uptake across the globe and the SH were attributed to both extended duration and increasing amplitude of C uptake. The shortened duration of uptake in the NH partly offsets the effects of increased NEE amplitude, making the net C uptake trend the same as that of the SH. The change in NEE IAV was also linked to changes in the amplitude and duration of uptake, but they worked in different ways in the NH, SH and globe. The fundamental attributions of amplitude and duration of C uptake revealed in this study are helpful to better understand the mechanisms underlying the trend and IAV of land C uptake. Our findings also suggest the critical roles of grassland and croplands in the NH in contributing to the trend and IAV of land C uptake.

Accumulation of phenanthrene by roots of intact wheat (Triticum acstivnm L.) seedlings: passive or active uptake?

PubMed Central

2010-01-01

Background Polycyclic aromatic hydrocarbons (PAHs) are of particular concern due to their hydrophobic, recalcitrant, persistent, potentially carcinogenic, mutagenic and toxic properties, and their ubiquitous occurrence in the environment. Most of the PAHs in the environment are present in surface soil. Plants grown in PAH-contaminated soils or water can become contaminated with PAHs because of their uptake. Therefore, they may threaten human and animal health. However, the mechanism for PAHs uptake by crop roots is little understood. It is important to understand exactly how PAHs are transported into the plant root system and into the human food chain, since it is beneficial in governing crop contamination by PAHs, remedying soils or waters polluted by PAHs with plants, and modeling potential uptake for risk assessment. Results The possibility that plant roots may take up phenanthrene (PHE), a representative of PAHs, via active process was investigated using intact wheat (Triticum acstivnm L.) seedlings in a series of hydroponic experiments. The time course for PHE uptake into wheat roots grown in Hoagland solution containing 5.62 μM PHE for 36 h could be separated into two periods: a fast uptake process during the initial 2 h and a slow uptake component thereafter. Concentration-dependent PHE uptake was characterized by a smooth, saturable curve with an apparent Km of 23.7 μM and a Vmax of 208 nmol g-1 fresh weight h-1, suggesting a carrier-mediated uptake system. Competition between PHE and naphthalene for their uptake by the roots further supported the carrier-mediated uptake system. Low temperature and 2,4-dinitrophenol (DNP) could inhibit PHE uptake equally, indicating that metabolism plays a role in PHE uptake. The inhibitions by low temperature and DNP were strengthened with increasing concentration of PHE in external solution within PHE water solubility (7.3 μM). The contribution of active uptake to total absorption was almost 40% within PHE water solubility. PHE uptake by wheat roots caused an increase in external solution pH, implying that wheat roots take up PHE via a PHE/nH+ symport system. Conclusion It is concluded that an active, carrier-mediated and energy-consuming influx process is involved in the uptake of PHE by plant roots. PMID:20307286

(68)Ga-DOTA-peptide: A novel molecular biomarker for nasopharyngeal carcinoma.

PubMed

Khor, Lih Kin; Loi, Hoi Yin; Sinha, Arvind Kumar; Tong, Kian Ti; Goh, Boon Cher; Loh, Kwok Seng; Lu, Suat-Jin

2016-04-01

Increased somatostatin receptor (SSTR) expression in patients with undifferentiated nasopharyngeal carcinoma (NPC) has been demonstrated with receptor autoradiography, (111) In-Octreotide scintigraphy, and (68) Ga-DOTA-TOC positron emission tomography (PET)/CT imaging. We sought to compare and correlate the uptake of fluorodeoxyglucose (FDG) and DOTA-NOC in undifferentiated NPC to ascertain the possible role of (68) Ga-DOTA-NOC PET/CT as a new imaging biomarker and to assess whether targeted peptide receptor radionuclide therapy is a feasible treatment option. After obtaining approval from our institutional review board, 4 patients with biopsy proven nonkeratinizing undifferentiated NPC who had just undergone routine staging/restaging (18) F-FDG PET/CT imaging were prospectively and consecutively recruited for (68) Ga-DOTA-NOC PET/CT imaging. Of these 4 patients, 3 were newly diagnosed with untreated NPC, whereas 1 patient was diagnosed with a case of recurrent NPC with previous treatment. These patients subsequently underwent (68) Ga-DOTA-NOC PET/CT within 10 days from the (18) F-FDG PET/CT to ensure lesion comparability. Tracer uptake in tumor lesions were assessed visually and semiquantitatively by measuring maximum standardized uptake values (SUVmax). There were 12 FDG-avid lesions of which 7 showed avid uptake of DOTA-NOC greater than liver uptake, whereas 5 showed low uptake of DOTA-NOC less than liver uptake. Subset analysis of the FDG-avid lesions at the primary and recurrent sites showed that all the FDG-avid primary tumors in the nasopharynx showed avid uptake of DOTA-NOC. On the contrary, the case of recurrent NPC showed avid FDG uptake but low DOTA-NOC uptake. Subset analysis of the suspicious FDG-avid cervical lymph nodes showed that 50% of them demonstrated avid DOTA-NOC uptake greater than liver uptake, whereas the remaining demonstrated low-grade DOTA-NOC uptake less than liver uptake. The 2 subcentimeter cervical lymph nodes that showed low-grade uptake of FDG lower than mediastinal blood pool activity were deemed to be reactive/inflammatory and showed low-grade uptake of DOTA-NOC. This study highlights the potential of (68) Ga-DOTA-peptide PET/CT as a new molecular biomarker for newly diagnosed undifferentiated NPC, and less so for recurrent NPC and metastatic nodes. This potentially opens up new diagnostic and therapeutic options in the management of undifferentiated NPC. © 2015 Wiley Periodicals, Inc.

Computed Tomography-Based Imaging of Voxel-Wise Lesion Water Uptake in Ischemic Brain: Relationship Between Density and Direct Volumetry.

PubMed

Broocks, Gabriel; Flottmann, Fabian; Ernst, Marielle; Faizy, Tobias Djamsched; Minnerup, Jens; Siemonsen, Susanne; Fiehler, Jens; Kemmling, Andre

2018-04-01

Net water uptake per volume of brain tissue may be calculated by computed tomography (CT) density, and this imaging biomarker has recently been investigated as a predictor of lesion age in acute stroke. However, the hypothesis that measurements of CT density may be used to quantify net water uptake per volume of infarct lesion has not been validated by direct volumetric measurements so far. The purpose of this study was to (1) develop a theoretical relationship between CT density reduction and net water uptake per volume of ischemic lesions and (2) confirm this relationship by quantitative in vitro and in vivo CT image analysis using direct volumetric measurements. We developed a theoretical rationale for a linear relationship between net water uptake per volume of ischemic lesions and CT attenuation. The derived relationship between water uptake and CT density was tested in vitro in a set of increasingly diluted iodine solutions with successive CT measurements. Furthermore, the consistency of this relationship was evaluated using human in vivo CT images in a retrospective multicentric cohort. In 50 edematous infarct lesions, net water uptake was determined by direct measurement of the volumetric difference between the ischemic and normal hemisphere and was correlated with net water uptake calculated by ischemic density measurements. With regard to in vitro data, water uptake by density measurement was equivalent to direct volumetric measurement (r = 0.99, P < 0.0001; mean ± SD difference, -0.29% ± 0.39%, not different from 0, P < 0.0001). In the study cohort, the mean ± SD uptake of water within infarct measured by volumetry was 44.7 ± 26.8 mL and the mean percent water uptake per lesion volume was 22.7% ± 7.4%. This was equivalent to percent water uptake obtained from density measurements: 21.4% ± 6.4%. The mean difference between percent water uptake by direct volumetry and percent water uptake by CT density was -1.79% ± 3.40%, which was not significantly different from 0 (P < 0.0001). Volume of water uptake in infarct lesions can be calculated quantitatively by relative CT density measurements. Voxel-wise imaging of water uptake depicts lesion pathophysiology and could serve as a quantitative imaging biomarker of acute infarct lesions.

Ethanol intake and sup 3 H-serotonin uptake I: A study in Fawn-Hooded rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daoust, M.; Compagnon, P.; Legrand, E.

1991-01-01

Ethanol intake and synaptosomal {sup 3}H-serotonin uptake were studied in male Fawn-Hooded and Sprague-Dawley rats. Fawn-Hooded rats consumed more alcohol and more water than Sprague-Dawley rats. Plasma alcohol levels of Sprague-Dawley rats were not detectable but were about 5 mg/dl in Fawn-Hooded rats. Ethanol intake increased the Vmax of serotonin uptake in Fawn-Hooded rats in hippocampus and cortex, but not in thalamus. In Fawn-Hooded rats, serotonin uptake (Vmax) was higher than in Sprague-Dawley rats cortex. Ethanol intake reduced the Vmax of serotonin uptake in Fawn-Hooded rats in hippocampus and cortex. In cortex, the carrier affinity for serotonin was increased inmore » alcoholized Fawn-Hooded rats. These results indicate that synaptosomal {sup 3}H-serotonin uptake is affected by ethanol intake. In Fawn-Hooded rats, high ethanol consumption is associated with high serotonin uptake. In rats presenting high serotonin uptake, alcoholization reduces {sup 3}H-serotonin internalization in synaptosomes, indicating a specific sensitivity to alcohol intake of serotonin uptake system.« less

Bounding the heterogeneous gas uptake on aerosols and ground using resistance model

NASA Astrophysics Data System (ADS)

Su, H.; Li, M.; Cheng, Y.

2017-12-01

Heterogeneous uptake on aerosols and ground are potential important atmospheric sinks for gases. Different schemes have been used to characterize the dry deposition and heterogeneous aerosol gas uptake, although they share similar characteristics. In this work, we propose a unified resistance model to compare the uptake flux on both ground and aerosols, to identify the dominate heterogeneous process within the planetary boundary layer (PBL). The Gamma(eq) is introduced to represent the reactive uptake coefficient on aerosols when these two processes are equally important. It's shown that Gamma(eq) is proportional to the dry deposition velocity, inversely proportional to aerosol surface area concentration. Under typical regional background condition, Gamma(eq) vary from 1x10-5 to 4x10-4 with gas species, land-use type and season, which indicates that aerosol gas uptake should be included in atmospheric models when uptake coefficient higher than 10-5. We address the importance of heterogeneous gas uptake on aerosols over ground especially for ozone uptake on liquid organic aerosols and for marine PBL atmosphere.

Silicon uptake and transport is an active process in Cucumis sativus.

PubMed

Liang, Yongchao; Si, Jin; Römheld, Volker

2005-09-01

Cucumis sativus is a species known to accumulate high levels of silicon (Si) in the tops, though the mechanism for its high Si uptake is little understood. In a series of hydroponic experiments, we examined uptake and xylem loading of Si in C. sativus along with Vicia faba at three levels of Si (0.085, 0.17 and 1.70 mm). Measured Si uptake in C. sativus was more than twice as high as calculated from the rate of transpiration assuming no discrimination between silicic acid and water in uptake. Measured Si uptake in V. faba, however, was significantly lower than the calculated uptake. Concentration of Si in xylem exudates was several-fold higher in C. sativus, but was significantly lower in V. faba compared with the Si concentration in external solutions, regardless of Si levels. Silicon uptake was strongly inhibited by low temperature and 2,4-dinitrophenol, a metabolic inhibitor, in C. sativus but not in V. faba. It can be concluded that Si uptake and transport in C. sativus is active and independent of external Si concentrations, in contrast to the process in V. faba.

Toward a transport-based analysis of nutrient spiraling and uptake in streams

USGS Publications Warehouse

Runkel, Robert L.

2007-01-01

Nutrient addition experiments are designed to study the cycling of nutrients in stream ecosystems where hydrologic and nonhydrologic processes determine nutrient fate. Because of the importance of hydrologic processes in stream ecosystems, a conceptual model known as nutrient spiraling is frequently employed. A central part of the nutrient spiraling approach is the determination of uptake length (SW), the average distance traveled by dissolved nutrients in the water column before uptake. Although the nutrient spiraling concept has been an invaluable tool in stream ecology, the current practice of estimating uptake length from steady-state nutrient data using linear regression (called here the "SW approach") presents a number of limitations. These limitations are identified by comparing the exponential SW equation with analytical solutions of a stream solute transport model. This comparison indicates that (1) SW, is an aggregate measure of uptake that does not distinguish between main channel and storage zone processes, (2) SW, is an integrated measure of numerous hydrologie and nonhydrologic processes-this process integration may lead to difficulties in interpretation when comparing estimates of SW, and (3) estimates of uptake velocity and areal uptake rate (Vf and U) based on S W, are not independent of system hydrology. Given these findings, a transport-based approach to nutrient spiraling is presented for steady-state and time-series data sets. The transport-based approach for time-series data sets is suggested for future research on nutrient uptake as it provides a number of benefits, including the ability to (1) separately quantify main channel and storage zone uptake, (2) quantify specific hydrologic and nonhydrologic processes using various model parameters (process separation), (3) estimate uptake velocities and areal uptake rates that are independent of hydrologic effects, and (4) use short-term, non-plateau nutrient additions such that the effects of regeneration and mineralization are minimized. In summary, the transport-based, time-series approach provides a means of estimating traditional measures of nutrient uptake (SW, V?? U) while providing additional information on the location and magnitude of uptake (main channel versus storage zone). Application of the transport-based approach to time-series data from Green Creek, Antarctica, indicates that the bulk of nitrate uptake (???74% to 100%) occurred within the main channel where benthic uptake by algal mats is a likely process. Substantial uptake (???26%) also occurred in the storage zone of one reach, where uptake is attributed to the microbial community.

Interference of 1:1 and 2:1 layered phyllosilicates as excipients with ranitidine.

PubMed

Li, Zhaohui; Fitzgerald, Nicole M; Albert, Zachary; Jiang, Wei-Teh

2016-04-01

As natural ingredients and excipients, kaolinite and talc were frequently studied for their interactions with drugs in pharmaceutical formulations. In this study, the uptake of ranitidine (RT) on these two minerals was studied under different physic-chemical conditions and the mechanism of RT uptake on these two minerals contrasted. Although the thermodynamic and kinetic RT uptake on these two minerals was similar and the RT uptake on both minerals were limited to the external surfaces only, drastic difference in RT uptake was found under different equilibrium solution pH and ionic strength conditions. As cation exchange process was strongly affected by solution pH and ionic strength, the RT uptake on kaolinite was dominated by cation exchange and electrostatic interactions, while the RT uptake on talc was more controlled by inter- and intra- molecular hydrogen bonding interactions. For kaolinite, the limiting factor for RT uptake was the specific surface area due to monolayer RT adsorption. In contract, multilayer RT uptake was found on talc surfaces. No matter which mechanism dominated RT uptake on these minerals, the interaction should not be neglected in pharmaceutical formulations should these minerals be used as additives and/or excipients. Copyright © 2015 Elsevier B.V. All rights reserved.

Rising atmospheric CO2 leads to large impact of biology on Southern Ocean CO2 uptake via changes of the Revelle factor

PubMed Central

Hauck, J; Völker, C

2015-01-01

The Southern Ocean is a key region for global carbon uptake and is characterized by a strong seasonality with the annual CO2 uptake being mediated by biological carbon drawdown in summer. Here we show that the contribution of biology to CO2 uptake will become even more important until 2100. This is the case even if biological production remains unaltered and can be explained by the decreasing buffer capacity of the ocean as its carbon content increases. The same amount of biological carbon drawdown leads to a more than twice as large reduction in CO2(aq) concentration and hence to a larger CO2 gradient between ocean and atmosphere that drives the gas exchange. While the winter uptake south of 44°S changes little, the summer uptake increases largely and is responsible for the annual mean response. The combination of decreasing buffer capacity and strong seasonality of biological carbon drawdown introduces a strong and increasing seasonality in the anthropogenic carbon uptake. Key Points Decrease of buffer capacity leads to stronger summer CO2 uptake in the future Biology will contribute more to future CO2 uptake in Southern Ocean Seasonality affects anthropogenic carbon uptake strongly PMID:26074650

GLUT4 Is Not Necessary for Overload-Induced Glucose Uptake or Hypertrophic Growth in Mouse Skeletal Muscle

PubMed Central

McMillin, Shawna L.; Schmidt, Denise L.; Kahn, Barbara B.

2017-01-01

GLUT4 is necessary for acute insulin- and contraction-induced skeletal muscle glucose uptake, but its role in chronic muscle loading (overload)-induced glucose uptake is unknown. Our goal was to determine whether GLUT4 is required for overload-induced glucose uptake. Overload was induced in mouse plantaris muscle by unilateral synergist ablation. After 5 days, muscle weights and ex vivo [3H]-2-deoxy-d-glucose uptake were assessed. Overload-induced muscle glucose uptake and hypertrophic growth were not impaired in muscle-specific GLUT4 knockout mice, demonstrating that GLUT4 is not necessary for these processes. To assess which transporters mediate overload-induced glucose uptake, chemical inhibitors were used. The facilitative GLUT inhibitor cytochalasin B, but not the sodium-dependent glucose cotransport inhibitor phloridzin, prevented overload-induced uptake demonstrating that GLUTs mediate this effect. To assess which GLUT, hexose competition experiments were performed. Overload-induced [3H]-2-deoxy-d-glucose uptake was not inhibited by d-fructose, demonstrating that the fructose-transporting GLUT2, GLUT5, GLUT8, and GLUT12 do not mediate this effect. To assess additional GLUTs, immunoblots were performed. Overload increased GLUT1, GLUT3, GLUT6, and GLUT10 protein levels twofold to fivefold. Collectively, these results demonstrate that GLUT4 is not necessary for overload-induced muscle glucose uptake or hypertrophic growth and suggest that GLUT1, GLUT3, GLUT6, and/or GLUT10 mediate overload-induced glucose uptake. PMID:28279980

[11C]choline uptake in regenerating liver after partial hepatectomy or CCl4-administration.

PubMed

Sasaki, Toru

2004-02-01

To characterize [methyl-(11)C]choline ([(11)C]choline) as an oncologic PET radiopharmaceutical, [(11)C]choline uptake in regenerating livers after partial hepatectomy as a model of typical proliferating tissue and after CCl(4) insult as that of proliferating tissue with inflammation, was studied in rats. [(11)C]Choline, [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG) and [2-(14)C]thymidine ([(14)C]TdR) uptake was studied in regenerating rat liver after 70% partial hepatectomy or CCl(4)-administration. [(11)C]Choline uptake in regenerating liver after partial hepatectomy was significantly increased with [(14)C]TdR uptake as a marker of DNA synthesis at 18 hours after surgery. On the other hand, the uptake was not accelerated by CCl(4)-administration, though it significantly increased [(14)C]TdR uptake. There were no differences of [(11)C]choline uptake acceleration following partial hepatectomy among the three parts of the regenerating liver. [(18)F]FDG uptake was accelerated in the regenerating liver on either partial hepatectomy or CCl(4)-administration. The magnitude of the increase in [(18)F]FDG uptake in the regenerating liver induced by partial hepatectomy was greater than that for [(11)C]choline. [(11)C]Choline uptake in the liver was accelerated by partial hepatectomy, but not by CCl(4)-administration. This might be expected given that the differentiation between proliferating tissues such as tumor and inflammatory tissue was possible by [(11)C]choline-PET.

Polyamine Uptake in Carrot Cell Cultures 1

PubMed Central

Pistocchi, Rossella; Bagni, Nello; Creus, José A.

1987-01-01

Putrescine and spermidine uptake into carrot (Daucus carota L.) cells in culture was studied. The time course of uptake showed that the two polyamines were very quickly transported into the cells, reaching a maximum absorption within 1 minute. Increasing external polyamine concentrations up to 100 millimolar showed the existence of a biphasic system with different affinities at low and high polyamine concentrations. The cellular localization of absorbed polyamines was such that a greater amount of putrescine was present in the cytoplasmic soluble fraction, while spermidine was mostly present in cell walls. The absorbed polyamines were released into the medium in the presence of increasing external concentrations of the corresponding polyamine or Ca2+. The effects of Ca2+ were different for putrescine and spermidine; putrescine uptake was slightly stimulated by 10 micromolar Ca2+ and inhibited by higher concentrations, while for spermidine uptake there was an increasing stimulation in the Ca2+ concentration range between 10 micromolar and 1 millimolar. La3+ nullified the stimulatory effect of 10 micromolar Ca2+ on putrescine uptake and that of 1 millimolar Ca2+ on spermidine uptake. La3+ at 0.5 to 1 millimolar markedly inhibited the uptake of both polyamines, suggesting that it interferes with the sites of polyamine uptake. Putrescine uptake was affected to a lesser extent by metabolic inhibitors than was spermidine uptake. It is proposed that the entry of polyamines into the cells is driven by the transmembrane electrical gradient, with a possible antiport mechanism between external and internal polyamine molecule. PMID:16665446

GLUT4 Is Not Necessary for Overload-Induced Glucose Uptake or Hypertrophic Growth in Mouse Skeletal Muscle.

PubMed

McMillin, Shawna L; Schmidt, Denise L; Kahn, Barbara B; Witczak, Carol A

2017-06-01

GLUT4 is necessary for acute insulin- and contraction-induced skeletal muscle glucose uptake, but its role in chronic muscle loading (overload)-induced glucose uptake is unknown. Our goal was to determine whether GLUT4 is required for overload-induced glucose uptake. Overload was induced in mouse plantaris muscle by unilateral synergist ablation. After 5 days, muscle weights and ex vivo [ 3 H]-2-deoxy-d-glucose uptake were assessed. Overload-induced muscle glucose uptake and hypertrophic growth were not impaired in muscle-specific GLUT4 knockout mice, demonstrating that GLUT4 is not necessary for these processes. To assess which transporters mediate overload-induced glucose uptake, chemical inhibitors were used. The facilitative GLUT inhibitor cytochalasin B, but not the sodium-dependent glucose cotransport inhibitor phloridzin, prevented overload-induced uptake demonstrating that GLUTs mediate this effect. To assess which GLUT, hexose competition experiments were performed. Overload-induced [ 3 H]-2-deoxy-d-glucose uptake was not inhibited by d-fructose, demonstrating that the fructose-transporting GLUT2, GLUT5, GLUT8, and GLUT12 do not mediate this effect. To assess additional GLUTs, immunoblots were performed. Overload increased GLUT1, GLUT3, GLUT6, and GLUT10 protein levels twofold to fivefold. Collectively, these results demonstrate that GLUT4 is not necessary for overload-induced muscle glucose uptake or hypertrophic growth and suggest that GLUT1, GLUT3, GLUT6, and/or GLUT10 mediate overload-induced glucose uptake. © 2017 by the American Diabetes Association.

Predictive Value of 99mTc-MAA SPECT for 90Y-Labeled Resin Microsphere Distribution in Radioembolization of Primary and Secondary Hepatic Tumors.

PubMed

Ilhan, Harun; Goritschan, Anna; Paprottka, Philipp; Jakobs, Tobias F; Fendler, Wolfgang P; Todica, Andrei; Bartenstein, Peter; Hacker, Marcus; Haug, Alexander R

2015-11-01

This study analyzed the predictive value of (99m)Tc-labeled macroaggregated albumin ((99m)Tc-MAA) SPECT for (90)Y-labeled resin microsphere therapy (radioembolization) by comparing uptake on pretherapeutic (99m)Tc-MAA SPECT with uptake on posttherapeutic (90)Y-bremsstrahlung SPECT. We included 502 patients (55% male; mean age ± SD, 62 ± 11 y) who underwent radioembolization between 2005 and 2013 because of primary or secondary liver malignancies (colorectal cancer [n = 195, 38.8%], neuroendocrine tumors [n = 77, 15.3%], breast cancer [n = 68, 13.5%], hepatocellular carcinoma [n = 59, 11.8%], cholangiocellular carcinoma [n = 40, 8.0%], or urologic tumors [n = 14, 2.8%]). Manually drawn regions of interest around tumors and adjacent healthy liver tissue for up to 3 lesions per patient on (99m)Tc-MAA and (90)Y-bremsstrahlung scans were used to quantify mean counts per pixel and evaluate the mean tumor-to-background ratio (TBR). Data were given as mean ± SD. Additionally, uptake in lesions on (99m)Tc-MAA and (90)Y-bremsstrahlung scans was graded visually as homogeneously higher than (grade 1), heterogeneously higher than (grade 2), equal to (grade 3), or lower than (grade 4) uptake in normal liver tissue. The Mann-Whitney U test and Spearman correlation were used to evaluate statistically significant differences between (99m)Tc-MAA and (90)Y-bremsstrahlung SPECT. In total, 1,008 lesions were analyzed. Of the 23% (230/1,008) of lesions that had grade 1 uptake on (99m)Tc-MAA SPECT, 81% (186/230) remained grade 1 after radioembolization whereas 16% (37/230) were grade 2. Of the lesions with grade 2 uptake on (99m)Tc-MAA SPECT, 16% had grade 1 uptake and 82% grade 2 uptake after radioembolization. Of the lesions with grade 3 uptake, however, 27% had grade 1 uptake and 47% grade 2 uptake after radioembolization. Even among the lesions with grade 4 uptake on (99m)Tc-MAA SPECT, 21% had grade 1 uptake and 46% grade 2 uptake after radioembolization. The mean TBR on (99m)Tc-MAA and (90)Y-bremsstrahlung SPECT showed a significant, though low, correlation in the total population (r = 0.26; P < 0.001) and in hepatocellular carcinoma (r = 0.4; P < 0.001), cholangiocellular carcinoma (r = 0.3; P < 0.05), breast cancer (r = 0.3; P < 0.001), colorectal cancer (r = 0.2; P < 0.001), and neuroendocrine tumors (r = 0.2; P < 0.01). Although significant for most lesions, the correlation between (99m)Tc-MAA and (90)Y-microsphere mean TBR was low. Classifying uptake into 4 grades revealed that lesions with high uptake on (99m)Tc-MAA SPECT maintain high uptake within radioembolization. More than 60% of lesions with a pretherapeutically lower uptake than in healthy liver tissue, however, showed high uptake within radioembolization. Patients with low tumor uptake on pretherapeutic (99m)Tc-MAA imaging should not be excluded from radioembolization. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Seasonal influenza vaccine uptake in HSE-funded hospitals and nursing homes during the 2011/2012 influenza season.

PubMed

O'Lorcain, P; Cotter, S; Hickey, L; O'Flanagan, D; Corcoran, B; O'Meara, M

2014-03-01

Annual seasonal influenza vaccine is recommended for all health care workers (HCWs) in Ireland. For the 2011/2012 influenza season, information was collected on influenza vaccination uptake among HCWs employed in Health Service Executive (HSE)-funded hospitals (primarily acute) and of nursing homes (NHs) and also among NH long-term and short-term respite care residents. Forty-five hospitals (80%) and 120 NHs (75%) provided uptake data. Nationally, influenza vaccine uptake among hospital employed HCWs was estimated to be 18% and 14% among HCWs in NHs; in NHs vaccine uptake among long-term care residents was estimated to 88%. These findings highlight the continued low uptake among HCWs of all categories and demonstrate the need for sustained measures to improve uptake rates.

Oncogene pathway activation in mammary tumors dictates [18F]-FDG-PET uptake

PubMed Central

Alvarez, James V.; Belka, George K.; Pan, Tien-chi; Chen, Chien-Chung; Blankemeyer, Eric; Alavi, Abass; Karp, Joel; Chodosh, Lewis A.

2015-01-01

Increased glucose utilization is a hallmark of human cancer that is used to image tumors clinically. In this widely used application, glucose uptake by tumors is monitored by positron emission tomography (PET) of the labeled glucose analog F-18-2-fluoro-2-deoxyglucose (18F-FDG). Despite its widespread clinical use, the cellular and molecular mechanisms that determine FDG uptake - a tool that can monitor tumor heterogeneity - remain poorly understood. In this study, we compared FDG uptake in mammary tumors driven by the Akt1, c-MYC, HER2/neu, Wnt1 or H-Ras oncogenes in genetically engineered mice, correlating it to tumor growth, cell proliferation and levels of gene expression involved in key steps of glycolytic metabolism. We found that FDG uptake by tumors was dictated principally by the driver oncogene and was not independently associated with tumor growth or cellular proliferation. Oncogene downregulation resulted in a rapid decrease in FDG uptake, preceding effects on tumor regression, irrespective of the baseline level of uptake. FDG uptake correlated positively with expression of hexokinase-2 (HK2) and HIF-1α and associated negatively with PFK-2b expression and p-AMPK. The correlation of HK2 and FDG uptake was independent of all variables tested, including the initiating oncogene, suggesting that HK2 is an independent predictor of FDG uptake. In contrast, expression of Glut1 was correlated with FDG uptake only in tumors driven by Akt or HER2/neu. Together, these results showed that the oncogenic pathway activated within a tumor is a primary determinant of its FDG uptake, mediated by key glycolytic enzymes that provide a framework to interpret effects on this key parameter in clinical imaging. PMID:25239452

Determinants of physiological uptake of 18F-fluorodeoxyglucose in palatine tonsils.

PubMed

Birkin, Emily; Moore, Katherine S; Huang, Chao; Christopher, Marshall; Rees, John I; Jayaprakasam, Vetrisudar; Fielding, Patrick A

2018-06-01

To determine the extent of physiological variation of uptake of F-flurodeoxyglucose (FDG) within palatine tonsils. To define normal limits for side-to-side variation and characterize factors affecting tonsillar uptake of FDG.Over a period of 16 weeks 299 adult patients at low risk for head and neck pathology, attending our center for FDG positron emission tomography/computed tomography (PET/CT) scans were identified. The maximum standardized uptake value (SUVmax) was recorded for each palatine tonsil. For each patient age, gender, smoking status, scan indication and prior tonsillectomy status as well as weather conditions were noted.There was a wide variation in palatine tonsil FDG uptake with SUVmax values between 1.3 and 11.4 recorded. There was a strong left to right correlation for tonsillar FDG uptake within each patient (P < .01). The right palatine tonsil showed increased FDG uptake (4.63) compared to the left (4.47) (P < .01). In multivariate analysis, gender, scan indication, and prevailing weather had no significant impact of tonsillar FDG uptake. Lower tonsillar uptake was seen in patients with a prior history of tonsillectomy (4.13) than those without this history (4.64) (P < .01). Decreasing tonsillar FDG uptake was seen with advancing age (P < .01). Significantly lower uptake was seen in current smokers (SUVmax 4.2) than nonsmokers (SUV 4.9) (P = .03).Uptake of FDG in palatine tonsils is variable but shows a strong side-to-side correlation. We suggest the left/ right SUVmax ratio as a guide to normality with a first to 99th percentiles of (0.70-1.36) for use in patients not suspected to have tonsillar pathology.

Increased choline uptake in macrophages and prostate cancer cells does not allow for differentiation between benign and malignant prostate pathologies.

PubMed

Schwarz, Timo; Seidl, Christof; Schiemann, Matthias; Senekowitsch-Schmidtke, Reingard; Krause, Bernd Joachim

2016-06-01

Inflammatory cells may contribute to the choline uptake in different prostate pathologies. The aim of this study was (i) to assess if inflammatory cells incorporate choline and (ii) to potentially detect differences compared to FDG uptake. Therefore we investigated the uptake of [(3)H]choline and [(18)F]FDG in human prostate carcinoma cells and human inflammatory cells. Macrophages were cultured from isolated mononuclear cells, gained by density gradient centrifugation of human buffy coats. T-lymphocytes, B-lymphocytes and granulocytes were enriched by density gradient centrifugation before cell sorting by means of flow cytometry was performed. [(3)H]choline and [(18)F]FDG uptake of isolated inflammatory cells as well as of LNCaP and PC-3 human prostate carcinoma cells was assessed simultaneously in dual tracer uptake experiments. Macrophages showed highest [(3)H]choline and [(18)F]FDG uptake compared to the tracer uptake rates of leukocytes. [(3)H]choline uptake of macrophages was in the same range as in prostate cancer cells. Lipopolysaccharide stimulation of macrophages resulted in an increase of [(18)F]FDG uptake in macrophages, but not in an increased [(3)H]choline uptake. The high [(3)H]choline uptake in macrophages may be a source of false-positive PET results in diagnosis of prostate cancer by choline-PET/CT. As already known from FDG-PET, discrimination between tumor and inflammation in prostate cancer patients is not possible via choline-PET. The application of choline-PET for reliable primary prostate cancer detection and delineation has to be queried. Copyright © 2016 Elsevier Inc. All rights reserved.

CAN ULTRASOUND ENABLE EFFICIENT INTRACELLULAR UPTAKE OF MOLECULES? A RETROSPECTIVE LITERATURE REVIEW AND ANALYSIS

PubMed Central

LIU, YING; YAN, JING; PRAUSNITZ, MARK R.

2012-01-01

Most applications of therapeutic ultrasound (US) for intracellular delivery of drugs, proteins, DNA/ RNA and other compounds would benefit from efficient uptake of these molecules into large numbers of cells without killing cells in the process. In this study we tested the hypothesis that efficient intracellular uptake of molecules can be achieved with high cell viability after US exposure in vitro. A search of the literature for studies with quantitative data on uptake and viability yielded 26 published papers containing 898 experimental data points. Analysis of these studies showed that just 7.7% of the data points corresponded to relatively efficient uptake (>50% of cells exhibiting uptake). Closer examination of the data showed that use of Definity US contrast agent (as opposed to Optison) and elevated sonication temperature at 37°C (as opposed to room temperature) were associated with high uptake, which we further validated through independent experiments carried out in this study. Although these factors contributed to high uptake, almost all data with efficient uptake were from studies that had not accounted for lysed cells when determining cell viability. Based on retrospective analysis of the data, we showed that not accounting for lysed cells can dramatically increase the calculated uptake efficiency. We further argue that if all the data considered in this study were re-analyzed to account for lysed cells, there would be essentially no data with efficient uptake. We therefore conclude that the literature does not support the hypothesis that efficient intracellular uptake of molecules can be achieved with high cell viability after US exposure in vitro, which poses a challenge to future applications of US that require efficient intracellular delivery. PMID:22425381

The Rate and Clinical Significance of Incidental Thyroid Uptake as Detected by Gallium-68 DOTATATE Positron Emission Tomography/Computed Tomography

PubMed Central

Nockel, Pavel; Millo, Corina; Keutgen, Xavier; Klubo-Gwiezdzinska, Joanna; Shell, Jasmine; Patel, Dhaval; Nilubol, Naris; Herscovitch, Peter; Sadowski, Samira M.

2016-01-01

Background: Gallium-68 (Ga-68) DOTATATE is a radiolabeled peptide–imaging modality that targets the somatostatin receptor (SSTR), especially subtype 2 (SSTR2). Benign and malignant thyroid tumors have been observed to express SSTR. The aim of this study was to evaluate the frequency and clinical significance of incidental atypical thyroid uptake as detected by Ga-68 DOTATATE positron emission tomography/computed tomography (PET/CT). Methods: A retrospective analysis was conducted of a prospective study in which 237 patients underwent Ga-68 DOTATATE PET/CT as part of a work-up for metastatic and unknown primary neuroendocrine tumors. The types of uptake in the thyroid gland (focal/diffuse) and maximum standardized uptake value (SUVmax) levels were evaluated and compared with the background uptake in the liver and salivary glands. Results: Of 237 patients, 26 (11%) had atypical thyroid uptake as detected by Ga-68 DOTATATE PET/CT. There were no significant clinical or biochemical variables associated with atypical thyroid uptake. Fourteen (54%) patients had positive focal uptake, and 12 (46%) patients had diffuse uptake. Of the 14 patients with atypical focal uptake, 10 (71%) had thyroid nodules on the corresponding side, as detected by anatomic imaging. Three of 10 patients (21%) were found to have papillary thyroid cancer, and seven (70%) had adenomatoid nodules. Of the 12 patients with diffuse increased uptake, six (50%) had a history of hypothyroidism, five (42%) had chronic lymphocytic thyroiditis, and one (8%) had nontoxic multinodular goiter. Conclusions: Patients with an incidental focal abnormal thyroid uptake on Ga-68 DOTATATE PET/CT scan should have further clinical evaluation to exclude a diagnosis of thyroid cancer. PMID:27094616

[Accumulation of S, Fe and Cd in rhizosphere of rice and their uptake in rice with different water managements].

PubMed

Zhang, Xue-Xia; Zhang, Xiao-Xia; Zheng, Yu-Ji; Wang, Rong-Ping; Chen, Neng-Chang; Lu, Pu-Xiang

2013-07-01

The interactions between the concentrations of sulfur, iron and cadmium in the rhizosphere and their uptakes in rice (Oryza sativa L. ) were studied using paddy soil which was contaminated by acid mine drainage under five water-management treatments of 60%, 80%, 100% field moisture capacity (FMC), flooded throughout the entire rice growth period and flooded followed by keeping 80% FMC after heading-flowering period. The water managements had no significant influence on the Fe and Cd concentrations in rhizosphere soil in maturity stage, although the concentration of Cd slightly increased with the increase of soil moisture in the tillering stage. However, the uptake of Fe and Cd in rice was obviously related to water managements. The increase of soil moisture enhanced the uptake of Fe, but decreased the uptake of Cd in different organs of rice (roots, stems and leaves, grains) except for Cd uptake of the root in the 60% FMC treatment. However, aerobic treatment after heading-flowering period enhanced Cd uptake in rice in all treatments, but did not influence the uptake of Fe in rice. On the other hand, the increase of soil moisture reduced the concentrations of total sulfur and available sulfur in the rhizosphere soil except for the 60% FMC treatment, which corresponded with the reduction of Cd uptake in rice. And the aerobic treatment promoted Cd uptake in rice, which was also positively related to the increase of total sulfur and available sulfur in rhizosphere soil. Therefore, it was concluded that the uptake and speciation of sulfur in rhizosphere soil other than the change of Fe concentration induced by water management could play an important role in Cd uptake of rice.

Follow-up bone scan in breast cancer patients: what is the appropriate interpretation of purely rib uptake?

PubMed

Seo, Minjung; Ko, Byung Kyun; Tae, Soon Young; Koh, Su-Jin; Noh, Young Ju; Choi, Hye-Jeong; Bae, Kyungkyg; Bang, Minseo; Jun, Sungmin; Park, Seol Hoon

2016-12-01

Although rib uptake is frequently detected in follow-up bone scans of breast cancer patients, few studies have assessed its clinical significance. Among 1208 breast cancer patients who underwent a bone scan between 2011 and 2014, 157 patients presented with newly detected rib uptake at follow-up. Patients who had underlying bone metastases (n=8) or had simultaneous new uptake in sites other than the rib (n=13) were excluded. The patients enrolled finally were those who had purely rib uptakes. The location, intensity, and final diagnosis of the uptake were evaluated by nuclear medicine physicians. A total of 275 new instances of rib uptake were detected in follow-up bone scans of 136 patients. These were more frequently located on the ipsilateral side of the breast cancer (61.1%) and the anterior arc (65.1%), and they presented as moderate to intense (93.1%) uptakes. Among these, 265 lesions in 130 patients turned out to be benign fractures (96.4%), whereas only 10 lesions in six patients were metastases. The proportion of metastases was significantly higher if the uptake was linear or if the patient had recurrence. It was marginally higher if the uptake was located in the posterior arc. The proportion of metastases within the radiation field was significantly lower in patients with a history of irradiation. Newly detected purely rib uptake on a follow-up bone scan in patients who have been treated for breast cancer is mostly because of fractures and rarely signals metastasis. However, if the patient has disease recurrence, metastasis should strongly be suspected, particularly when uptake is linear or located in the posterior arc.

Survival analysis of time to uptake of modern contraceptives among sexually active women of reproductive age in Nigeria

PubMed Central

Adebowale, Ayo Stephen; Morhason-Bello, ImranOludare

2015-01-01

Objective To assess the timing of modern contraceptive uptake among married and never-married women in Nigeria. Design A retrospective cross-sectional study. Data and method We used nationally representative 2013 Demographic and Health Survey data in Nigeria. Modern contraceptive uptake time was measured as the period between first sexual intercourse and first use of a modern contraceptive. Non-users of modern contraceptives were censored on the date of the survey. Kaplan–Meier survival curves were used to determine the rate of uptake. A Cox proportional-hazards model was used to determine variables influencing the uptake at 5% significance level. Participants A total of 33 223 sexually active women of reproductive age. Outcome measure Time of uptake of a modern contraceptive after first sexual intercourse. Results The median modern contraceptive uptake time was 4 years in never-married and 14 years among ever-married women. Significant differences in modern contraceptive uptake existed in respondents’ age, location, education and wealth status. Never-married women were about three times more likely to use a modern contraceptive than ever-married women (aHR=3.24 (95% CI 2.82 to 3.65)). Women with higher education were six times more likely to use a modern contraceptive than those without education (aHR=6.18 (95% CI 5.15 to 7.42)). Conclusions The rate of modern contraceptive uptake is low, and timing of contraceptive uptake during or after first sexual intercourse differed according to marital status. Age and number of children ever born influenced modern contraceptive uptake among the never-married women, but religion and place of residence were associated with the probability of modern contraceptive uptake among ever-married women. PMID:26671948

Selected Phytochemicals and Culinary Plant Extracts Inhibit Fructose Uptake in Caco-2 Cells.

PubMed

Lee, Yurim; Lim, Yeni; Kwon, Oran

2015-09-18

This study compared the ability of nine culinary plant extracts containing a wide array of phytochemicals to inhibit fructose uptake and then explored the involvement of intestinal fructose transporters and phytochemicals for selected samples. The chemical signature was characterized by high performance liquid chromatography with mass spectrometry. Inhibition of [(14)C]-fructose uptake was tested by using human intestinal Caco-2 cells. Then, the relative contribution of the two apical-facing intestinal fructose transporters, GLUT2 and GLUT5, and the signature components for fructose uptake inhibition was confirmed in naive, phloretin-treated and forskolin-treated Caco-2 cells. HPLC/MS analysis of the chemical signature revealed that guava leaf contained quercetin and catechin, and turmeric contained curcumin, bisdemethoxycurcumin and dimethoxycurcumin. Similar inhibition of fructose uptake (by ~50%) was observed with guava leaf and turmeric in Caco-2 cells, but with a higher contribution of GLUT2 for turmeric and that of GLUT5 for guava leaf. The data suggested that, in turmeric, demethoxycurcumin specifically contributed to GLUT2-mediated fructose uptake inhibition, and curcumin did the same to GLUT5-mediated fructose uptake inhibition, but GLUT2 inhibition was more potent. By contrast, in guava leaf, catechin specifically contributed to GLUT5-mediated fructose uptake inhibition, and quercetin affected both GLUT5- and GLUT2-mediated fructose uptake inhibition, resulting in the higher contribution of GLUT5. These results suggest that demethoxycurcumin is an important contributor to GLUT2-mediated fructose uptake inhibition for turmeric extract, and catechin is the same to GLUT5-mediated fructose uptake inhibition for guava leaf extract. Quercetin, curcumin and bisdemethoxycurcumin contributed to both GLUT5- and GLUT2-mediated fructose uptake inhibition, but the contribution to GLUT5 inhibition was higher than the contribution to GLUT2 inhibition.

Atmospheric nitrous oxide uptake in boreal spruce forest soil

NASA Astrophysics Data System (ADS)

Siljanen, Henri; Welti, Nina; Heikkinen, Juha; Biasi, Christina; Martikainen, Pertti

2017-04-01

Nitrous oxide (N2O) uptake from the atmosphere has been found in forest soils but environmental factors controlling the uptake and its atmospheric impact are poorly known. We measured N2O fluxes over growing season in a boreal spruce forest having control plots and plots with long nitrogen fertilization history. Also methane (CH4) fluxes were measured to compare the atmospheric impact of N2O and CH4fluxes. Soil chemical and physical characteristics and climatic conditions were measured as background data. Nitrous oxide consumption and uptake mechanisms were measured in complementary laboratory incubation experiments using stable isotope approaches. Gene transcript numbers of nitrous oxide reductase (nosZ) I and II genes were quantified along the incubation with elevated N2O atmosphere. The spruce forests without fertilization history showed highest N2O uptake rates whereas pine forest had low emissions. Nitrous oxide uptake correlated positively with soil moisture, high soil silt content, and low temperature. Nitrous oxide uptake varied seasonally, being highest in spring and autumn when temperature was low and water content was high. The spruce forest was sink for CH4.Methane fluxes were decoupled from the N2O fluxes (i.e. when the N2O uptake was high the CH4 uptake was low). By using GWP approach, the cooling effect of N2O uptake was on average 30% of the cooling effect of CH4 uptake in spruce forest without fertilization. Anoxic conditions promoted higher N2O consumption rates in all soils. Gene transcription of nosZ-I genes were activated at beginning of the incubation. However, atypical/clade-II nosZ was not detected. These results suggests, that also N2O uptake rates have to be considered when accounting for the GHG budget of spruce forests.

Uptake of acetaldehyde-modified (ethylated) low-density lipoproteins by mouse peritoneal macrophages.

PubMed

Wehr, Hanna; Mirkiewicz, Ewa; Rodo, Maria; Bednarska-Makaruk, Malgorzata

2002-04-01

The uptake of acetaldehyde-modified (ethylated) low-density lipoproteins (LDLs) by murine peritoneal macrophages is described and compared with the uptake of acetylated LDLs. The fluorescent marker DiI was used. No competition between ethylated and acetylated LDLs was observed. Ethylated LDL uptake was not inhibited by polyinosinic acid or fucoidin. Our conclusion is that uptake of ethylated and acetylated LDLs can be done by two different receptors.

Metabolic effects of growth factors and polycyclic aromatic hydrocarbons on cultured human placental cells of early and late gestation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guyda, H.J.

1991-03-01

The metabolic effects of epidermal growth factor (EGF), insulin, insulin-like growth factor-I (IGF-I), and IGF-II were determined on human placental cells in monolayer culture obtained from early gestation (less than 20 weeks) and late gestation (38-42 weeks). Parameters studied were uptake of aminoisobutyric acid (AIB), uptake of 3-O-methylglucose and (3H)thymidine incorporation into cell protein. Since benzo(alpha)pyrene (BP) inhibits EGF binding and autophosphorylation in cultured human placental cells, particularly in early gestation, we also studied the effect of benzo(alpha)pyrene and other polycyclic aromatic hydrocarbons (PAHs) on EGF-mediated AIB uptake. The metabolic effects of EGF, insulin, and the IGFs in cultured humanmore » placental cells varied with gestational age and the growth factor studied. All three classes of growth factors stimulated AIB uptake in both early and late gestation at concentrations from 10-100 micrograms/L, well within a physiological range. However, insulin stimulation of AIB uptake was maximal at a high concentration in both early and late gestation cells, suggesting an action via type 1 IGF receptors rather than via insulin receptors. EGF stimulated 3-O-methylglucose uptake only in term placental cells. No significant stimulation of (3H)thymidine incorporation by any of the growth factors tested was seen with either early or late gestation cells. The effect of PAHs on AIB uptake by cultured placental cells was variable. BP alone stimulated AIB uptake by both very early and late gestation cells and enhanced EGF-stimulated AIB uptake. alpha-naphthoflavone alone inhibited AIB uptake at all gestational ages and inhibited EGF-stimulated AIB uptake. beta-Naphthoflavone and 3-methylcholanthrene minimally inhibited AIB uptake by early gestation cells and did not modify EGF-stimulated uptake at any gestational period.« less

Heterogeneous uptake of ammonia and dimethylamine into sulfuric and oxalic acid particles

NASA Astrophysics Data System (ADS)

Sauerwein, Meike; Keung Chan, Chak

2017-05-01

Heterogeneous uptake is one of the major mechanisms governing the amounts of short-chain alkylamines and ammonia (NH3) in atmospheric particles. Molar ratios of aminium to ammonium ions detected in ambient aerosols often exceed typical gas phase ratios. The present study investigated the simultaneous uptake of dimethylamine (DMA) and NH3 into sulfuric and oxalic acid particles at gaseous DMA / NH3 molar ratios of 0.1 and 0.5 at 10, 50 and 70 % relative humidity (RH). Single-gas uptake and co-uptake were conducted under identical conditions and compared. Results show that the particulate dimethyl-aminium/ammonium molar ratios (DMAH / NH4) changed substantially during the uptake process, which was severely influenced by the extent of neutralisation and the particle phase state. In general, DMA uptake and NH3 uptake into concentrated H2SO4 droplets were initially similarly efficient, yielding DMAH / NH4 ratios that were similar to DMA / NH3 ratios. As the co-uptake continued, the DMAH / NH4 gradually dropped due to a preferential uptake of NH3 into partially neutralised acidic droplets. At 50 % RH, once the sulfate droplets were neutralised, the stronger base DMA displaced some of the ammonium absorbed earlier, leading to DMAH / NH4 ratios up to four times higher than the corresponding gas phase ratios. However, at 10 % RH, crystallisation of partially neutralised sulfate particles prevented further DMA uptake, while NH3 uptake continued and displaced DMAH+, forming almost pure ammonium sulfate. Displacement of DMAH+ by NH3 has also been observed in neutralised, solid oxalate particles. The results can explain why DMAH / NH4 ratios in ambient liquid aerosols can be larger than DMA / NH3, despite an excess of NH3 in the gas phase. An uptake of DMA to aerosols consisting of crystalline ammonium salts, however, is unlikely, even at comparable DMA and NH3 gas phase concentrations.

Trends and timing of cigarette smoking uptake among US young adults: survival analysis using annual national cohorts from 1976 to 2005.

PubMed

Terry-McElrath, Yvonne M; O'Malley, Patrick M

2015-07-01

To measure changes over time in cigarette smoking uptake prevalence and timing during young adulthood (ages 19-26 years), and associations between time-invariant/-varying characteristics and uptake prevalence/timing. Discrete-time survival modeling of data collected from United States high school seniors (modal age 17/18) enrolled in successive graduating classes from 1976 to 2005 and participating in four follow-up surveys (to modal age 25/26). The longitudinal component of the Monitoring the Future study. A total of 10 758 individuals reporting no life-time smoking when first surveyed as high school seniors. Smoking uptake (any, experimental, occasional and regular); socio-demographic variables; marital, college and work status; time spent socializing. The percentage of young adults moving from non-smoker to experimental smoking [slope estimate 0.11, standard error (SE) = 0.04, P = 0.005] or occasional smoking (slope estimate 0.17, SE = 0.03, P < 0.001) increased significantly across graduating classes; the percentage moving from non-smoker to regular smoker remained stable. All forms of smoking uptake were most likely to occur at age 19/20, but uptake prevalence at older ages increased over time [e.g. cohort year predicting occasional uptake at modal age 25/26 adjusted hazard odds ratio (AHOR) = 1.05, P = 0.002]. Time-invariant/-varying characteristics had unique associations with the timing of various forms of smoking uptake (e.g. at modal age 21/22, currently attending college increased occasional uptake risk (AHOR = 2.11, P < 0.001) but decreased regular uptake risk (AHOR = 0.69, P = 0.026). Young adult occasional and experimental smoking uptake increased in the United States for non-smoking high school seniors graduating from 1976 to 2005. Smoking uptake for these cohorts remained most likely to occur at age 19/20, but prevalence of uptake at older ages increased. © 2015 Society for the Study of Addiction.

Direct determination of the driving forces for taurocholate uptake into rat liver plasma membrane vesicles.

PubMed

Duffy, M C; Blitzer, B L; Boyer, J L

1983-10-01

To determine directly the driving forces for bile acid entry into the hepatocyte, the uptake of [3H]taurocholic acid into rat liver plasma membrane vesicles was studied. The membrane preparation contained predominantly right-side-out vesicles, and was highly enriched in plasma membrane marker enzymes. The uptake of taurocholate at equilibrium was inversely related to medium osmolarity, indicating transport into an osmotically sensitive space. In the presence of an inwardly directed sodium gradient (NaCl or sodium gluconate), the initial rate of uptake was rapid and taurocholate was transiently accumulated at a concentration twice that at equilibrium (overshoot). Other inwardly directed cation gradients (K+, Li+, choline+) or the presence of sodium in the absence of a gradient (Na+ equilibrated) resulted in a slower initial uptake rate and did not sustain an overshoot. Bile acids inhibited sodium-dependent taurocholate uptake, whereas bromsulphthalein inhibited both sodium-dependent and sodium-independent uptake and D-glucose had no effect on uptake. Uptake was temperature dependent, with maximal overshoots occurring at 25 degrees C. Imposition of a proton gradient across the vesicle (pHo less than pHi) in the absence of a sodium gradient failed to enhance taurocholate uptake, indicating that double ion exchange (Na+-H+, OH- -anion) is unlikely. Creation of a negative intravesicular potential by altering accompanying anions or by valinomycin-induced K+-diffusion potentials did not enhance taurocholate uptake, suggesting an electroneutral transport mechanism. The kinetics of taurocholate uptake demonstrated saturability with a Michaelis constant at 52 microM and maximum velocity of 4.5 nmol X mg-1 X protein X min-1. These studies provide definitive evidence for a sodium gradient-dependent, carrier-mediated, electrically neutral transport mechanism for hepatic taurocholate uptake. These findings are consistent with a model for bile secretion in which the basolateral enzyme Na+,K+-ATPase provides the driving force for "uphill" bile acid transport by establishing a trans-membrane sodium gradient.

Novel single skeletal muscle fiber analysis reveals a fiber type-selective effect of acute exercise on glucose uptake.

PubMed

Cartee, Gregory D; Arias, Edward B; Yu, Carmen S; Pataky, Mark W

2016-11-01

One exercise session can induce subsequently elevated insulin sensitivity that is largely attributable to greater insulin-stimulated glucose uptake by skeletal muscle. Because skeletal muscle is a heterogeneous tissue comprised of diverse fiber types, our primary aim was to determine exercise effects on insulin-independent and insulin-dependent glucose uptake by single fibers of different fiber types. We hypothesized that each fiber type featuring elevated insulin-independent glucose uptake immediately postexercise (IPEX) would be characterized by increased insulin-dependent glucose uptake at 3.5 h postexercise (3.5hPEX). Rat epitrochlearis muscles were isolated and incubated with 2-[ 3 H]deoxyglucose. Muscles from IPEX and sedentary (SED) controls were incubated without insulin. Muscles from 3.5hPEX and SED controls were incubated ± insulin. Glucose uptake (2-[ 3 H]deoxyglucose accumulation) and fiber type (myosin heavy chain isoform expression) were determined for single fibers dissected from the muscles. Major new findings included the following: 1) insulin-independent glucose uptake was increased IPEX in single fibers of each fiber type (types I, IIA, IIB, IIBX, and IIX), 2) glucose uptake values from insulin-stimulated type I and IIA fibers exceeded the values for the other fiber types, 3) insulin-stimulated glucose uptake for type IIX exceeded IIB fibers, and 4) the 3.5hPEX group vs. SED had greater insulin-stimulated glucose uptake in type I, IIA, IIB, and IIBX but not type IIX fibers. Insulin-dependent glucose uptake was increased at 3.5hPEX in each fiber type except for IIX fibers, although insulin-independent glucose uptake was increased IPEX in all fiber types (including type IIX). Single fiber analysis enabled the discovery of this fiber type-related difference for postexercise, insulin-stimulated glucose uptake. Copyright © 2016 the American Physiological Society.

Microbial Enzyme Activity, Nutrient Uptake, and Nutrient Limitation in Forested Streams

EPA Science Inventory

We measured NH4 + and PO4 -3 uptake length (Sw), uptake velocity (Vf), uptake rate (U), biofilm enzyme activity (BEA), and channel geomorphology in streams draining forested catchments in the Northwestern (Northern California Coast Range and Cascade Mountains) and Southeastern (A...

[Effects of carbon sources, temperature and electron acceptors on biological phosphorus removal].

PubMed

Han, Yun; Xu, Song; Dong, Tao; Wang, Bin-Fan; Wang, Xian-Yao; Peng, Dang-Cong

2015-02-01

Effects of carbon sources, temperature and electron acceptors on phosphorus uptake and release were investigated in a pilot-scale oxidation ditch. Phosphorus uptake and release rates were measured with different carbon sources (domestic sewage, sodium acetate, glucose) at 25 degrees C. The results showed that the minimum phosphorus uptake and release rates of glucose were 5.12 mg x (g x h)(-1) and 6.43 mg x (g x h)(-1), respectively, and those of domestic sewage are similar to those of sodium acetate. Phosphorus uptake and release rates increased with the increase of temperature (12, 16, 20 and 25 degrees C) using sodium acetate as carbon sources. Anoxic phosphorus uptake rate decreased with added COD. Electron acceptors (oxygen, nitrate, nitrite) had significant effects on phosphorus uptake rate and their order was in accordance with oxygen > nitrate > nitrite. The mass ratio of anoxic P uptake and N consumption (P(uptake)/N (consumption)) of nitrate and nitrite were 0.96 and 0.65, respectively.

Carrier-mediated uptake of nobiletin, a citrus polymethoxyflavonoid, in human intestinal Caco-2 cells.

PubMed

Kimura, Osamu; Ohta, Chiho; Koga, Nobuyuki; Haraguchi, Koichi; Kato, Yoshihisa; Endo, Tetsuya

2014-07-01

The mechanism of intestinal absorption of nobiletin (NBL) was investigated using Caco-2 cells. The uptake of NBL from the apical membranes of Caco-2 cells was rapid and temperature-dependent and the presence of metabolic inhibitors, NaN3 and carbonylcyanide p-trifluoromethoxyphenylhydrazone, did not cause a decrease in NBL uptake. The relationship between the initial uptake of NBL and its concentration was saturable, suggesting the involvement of a carrier-mediated process. The Km and uptake clearance (Vmax/Km) values for NBL were 50.6 and 168.1μl/mg protein/min, respectively. This clearance value was about 9-fold greater than that of the non-saturable uptake clearance (Kd: 18.5μl/mg protein/min). The presence of structurally similar compounds, such as quercetin and luteolin, competitively inhibited NBL uptake. These results suggest that uptake of NBL from the apical membranes of Caco-2 cells is mainly mediated by an energy-independent facilitated diffusion process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Divalent cation mobility throughout exponential growth and sporulation of Bacillus megaterium.

PubMed

Krueger, W B; Kolodziej, B J

1978-01-01

Each of the five elements considered was taken up by Bacillus megaterium during exponential growth. Initial Mg and Mn uptake was rapid and ended by mid-log. For Ca, Fe, and Zn, uptake continued throughout exponential growth. Elements were released from the cells immediately following initial uptake. For Mn, egression continued to t2, with release of 36% of total accumulated. Secondary uptake followed immediately and continued through stage V. Magnesium egression continued to t1 with release of 33% accumulated. Secondary uptake began by t5 (stage IV) and continued slowly through sporulation. Calcium egression ceased by t4 with release of 25% total accumulated. Secondary uptake began by t6 (stage V) and continued until depleted. Zinc egression stopped by t5 with release of 34% accumulated with some secondary uptake by stage V. Iron egression terminated at t4 with release of 59% of total accumulated. This was followed by secondary uptake after t12 (stage VI).

Phased introduction of a universal childhood influenza vaccination programme in England: population-level factors predicting variation in national uptake during the first year, 2013/14.

PubMed

Green, H K; Andrews, N; Letley, L; Sunderland, A; White, J; Pebody, R

2015-05-21

Through a phased rollout, the UK is implementing annual influenza vaccination for all healthy children aged 2-16 years old. In the first year of the programme in England in 2013/14, all 2-3 year olds were offered influenza vaccine through primary care and a primary school age programme was piloted, mainly through schools, in geographically distinct areas. Equitable delivery is a key aim of the programme; it is unclear if concerns by some religious groups over influenza vaccine content have impacted on uptake. At the end of the 2013/14 season, variations in uptake for 2-3 year olds and 4-11 year olds were assessed and stratified by population-level predictors: deprivation, ethnicity, religious beliefs and rurality. GP practice or school level uptake was linearly regressed against these variables to determine potential predictors and changes in uptake, adjusting for significant factors. Uptake varied considerably by geographic locality for both 2-3 year olds and 4-11 year olds. Lower uptake was seen in increasingly deprived areas, with an adjusted uptake in the most deprived quintile 12% and 8% lower than the least deprived areas by age-group respectively. By ethnicity, the highest non-white population quartile had an adjusted uptake 9% and 14% lower than the lowest non-white quartile by age-group respectively. Uptake also varied according to religious beliefs, with adjusted uptake in 4-11 year olds in the highest Muslim population tertile 8% lower than the lowest Muslim population tertile. In the first season of the childhood influenza vaccination programme, uptake was not uniform across the country, with deprivation and ethnicity both predictors of low uptake in pre-school and primary school age children, and religious beliefs also an important factor, particularly the latter group. With the continued rollout of the programme, these population-level factors should be addressed to achieve sustained successful uptake, along with assessment of contribution of individual and household-level factors. Copyright © 2015. Published by Elsevier Ltd.

Ethanol intake and sup 3 H-serotonin uptake II: A study in alcoholic patients using platelets sup 3 H-paroxetine binding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daoust, M.; Boucly, P.; Ernouf, D.

1991-01-01

The kinetic parameters of {sup 3}H-paroxetine binding and {sup 3}H-serotonin uptake were studied in platelets of alcoholic patients. There was no difference between alcoholic and non alcoholic subjects in {sup 3}H-paroxetine binding. When binding and {sup 3}H-serotonin uptake were studied, in the same plasma of the same subjects, the Vmax of serotonin uptake was increased in alcoholics. The data confirm the involvement of serotonin uptake system in alcohol dependance and suggest that serotonin uptake and paroxetine binding sites may be regulated independently in this pathology.

The varying influence of socioeconomic deprivation on breast cancer screening uptake in London.

PubMed

Jack, Ruth H; Robson, Tony; Davies, Elizabeth A

2016-06-01

We assessed the relationship between screening uptake and socioeconomic deprivation for London women aged 50-52 invited to their first routine screening appointment between 2006 and 2009. We examined uptake for London overall and within six screening areas, using deprivation quintile, based on post code of residence. After adjustment for age, area and ethnicity, overall uptake decreased with increasing deprivation (adjusted odds ratio (OR) = 0.95, P < 0.001). However, in two screening areas with lower uptake, women living in deprived areas had higher uptake than women from affluent areas. These potential inequalities in early diagnosis across London require further investigation. © Crown copyright 2015.

Uptake and withdrawal of droplets from carbon nanotubes.

PubMed

Schebarchov, D; Hendy, S C

2011-01-01

We give an account of recent studies of droplet uptake and withdrawal from carbon nanotubes using simple theoretical arguments and molecular dynamics simulations. Firstly, the thermodynamics of droplet uptake and release is considered and tested via simulation. We show that the Laplace pressure acting on a droplet assists capillary uptake, allowing sufficiently small non-wetting droplets to be absorbed. We then demonstrate how the uptake and release of droplets of non-wetting fluids can be exploited for the use of carbon nanotubes as nanopipettes. Finally, we extend the Lucas-Washburn model to deal with the dynamics of droplet capillary uptake, and again test this by comparison with molecular dynamics simulations.

Uptake and withdrawal of droplets from carbon nanotubes

NASA Astrophysics Data System (ADS)

Schebarchov, D.; Hendy, S. C.

2011-01-01

We give an account of recent studies of droplet uptake and withdrawal from carbon nanotubes using simple theoretical arguments and molecular dynamics simulations. Firstly, the thermodynamics of droplet uptake and release is considered and tested via simulation. We show that the Laplace pressure acting on a droplet assists capillary uptake, allowing sufficiently small non-wetting droplets to be absorbed. We then demonstrate how the uptake and release of droplets of non-wetting fluids can be exploited for the use of carbon nanotubes as nanopipettes. Finally, we extend the Lucas-Washburn model to deal with the dynamics of droplet capillary uptake, and again test this by comparison with molecular dynamics simulations.

99mTc-HYNIC-TOC increased uptake can mimic malignancy in the pancreas uncinate process at somatostatin receptor SPECT/CT.

PubMed

Yamaga, Lilian Yuri Itaya; Neto, Guilherme Campos Carvalho; da Cunha, Marcelo Livorsi; Osawa, Akemi; Oliveira, Julio Cesar Silveira; Fonseca, Ricardo Quartim; Nogueira, Solange Amorim; Wagner, Jairo; Funari, Marcelo Gusmão

2016-03-01

The aim of this study was to assess the occurrence and frequency of increased physiologic uptake of 99mTc-HYNIC-TOC by the uncinate process of the pancreas in SPECT/CT images. Forty-six scans of 41 patients were evaluated retrospectively. The uptake of 99mTc-HYNIC-TOC was considered to be physiologic in patients with normal findings at dedicated abdominal CT or MR and lack of neoplastic lesions in clinical follow-ups. The intensity of uncinate process uptake was compared to the uptake of the normal liver. Focal uptake was attributed to the presence of pancreatic NET in 5 patients. Among the 36 patients without any evidence of malignancy in CT, MR and follow-up, 7 (19.4 %) showed increased uptake in the uncinate process. The intensity of uptake was lesser in 3 (8.3 %), similar in 3 and greater than the normal liver in 1 (2.8 %) case. Increased 99mTc-HYNIC-TOC uptake occurred in 19.4 % of those subjects without any evidence of neuroendocrine tumor in the uncinate process.

Tea and coffee time with bacteria - Investigation of uptake of key coffee and tea phenolics by wild type E. coli.

PubMed

Hakeem Said, Inamullah; Gencer, Selin; Ullrich, Matthias S; Kuhnert, Nikolai

2018-06-01

Dietary phenolic compounds are often transformed by gut microbiota prior to absorption. This transformation may modulate their biological activities. Many fundamental questions still need to be addressed to understand how the gut microbiota-diet interactions affect human health. Herein, a UHPLC-QTOF mass spectrometry-based method for the quantification of uptake and determination of intracellular bacterial concentrations of dietary phenolics from coffee and tea was developed. Quantitative uptake data for selected single purified phenolics were determined. The specific uptake from mixtures containing up to four dietary relevant compounds was investigated to assess changes of uptake parameters in a mixture model system. Indeed, perturbation of bacteria by several compounds alters uptake parameter in particular t max . Finally, model bacteria were dosed with complex dietary mixtures such as diluted tea or coffee extracts. The uptake kinetics of the twenty most abundant phenolics was quantified and the findings are discussed. For the first time, quantitative data on in-vitro uptake of dietary phenolics from food matrices were obtained indicating a time-dependent differential uptake of nutritional compounds. Copyright © 2018. Published by Elsevier Ltd.

Native low-density lipoprotein uptake by macrophage colony-stimulating factor-differentiated human macrophages is mediated by macropinocytosis and micropinocytosis.

PubMed

Anzinger, Joshua J; Chang, Janet; Xu, Qing; Buono, Chiara; Li, Yifu; Leyva, Francisco J; Park, Bum-Chan; Greene, Lois E; Kruth, Howard S

2010-10-01

To examine the pinocytotic pathways mediating native low-density lipoprotein (LDL) uptake by human macrophage colony-stimulating factor-differentiated macrophages (the predominant macrophage phenotype in human atherosclerotic plaques). We identified the kinase inhibitor SU6656 and the Rho GTPase inhibitor toxin B as inhibitors of macrophage fluid-phase pinocytosis of LDL. Assessment of macropinocytosis by time-lapse microscopy revealed that both drugs almost completely inhibited macropinocytosis, although LDL uptake and cholesterol accumulation by macrophages were only partially inhibited (approximately 40%) by these agents. Therefore, we investigated the role of micropinocytosis in mediating LDL uptake in macrophages and identified bafilomycin A1 as an additional partial inhibitor (approximately 40%) of macrophage LDL uptake that targeted micropinocytosis. When macrophages were incubated with both bafilomycin A1 and SU6656, inhibition of LDL uptake was additive (reaching 80%), showing that these inhibitors target different pathways. Microscopic analysis of fluid-phase uptake pathways in these macrophages confirmed that LDL uptake occurs through both macropinocytosis and micropinocytosis. Our findings show that human macrophage colony-stimulating factor-differentiated macrophages take up native LDL by macropinocytosis and micropinocytosis, underscoring the importance of both pathways in mediating LDL uptake by these cells.

Possible mechanisms of stimulatory action of papaverine on calcium-uptake by rat uterine microsomal fraction.

PubMed

Koike, K; Takayanagi, I

1981-10-01

Effects of papaverine and cyclic AMP on Ca-uptake by the microsomal fraction from rat uterus were studied. Papaverine (3 x 10(-5) M) potentiated Ca-uptake by the microsomal fraction in the presence of potassium oxalate. However, cyclic AMP and MIX (3-isobutyl-1-methylxanthine; 1 mM), a potent phosphodiesterase inhibitor, did not influence Ca-uptake by the microsomal fraction in the presence of potassium oxalate. Cyclic AMP in concentrations of 10(-8) to 10(-4) M did not influence Ca-uptake by the microsomal fraction in the presence of potassium oxalate. In the absence of potassium oxalate, papaverine and Aspaminol (1,1,-diphenyl-3-piperidinobutanol hydrochloride), a nonspecific smooth muscle relaxant, inhibited Ca-uptake by the microsomal fraction and cyclic AMP had no influence on this uptake. These results suggest that papaverine potentiated Ca-uptake by membranes such as sarcoplasmic reticulum, in the presence of potassium oxalate and inhibited Ca-uptake by the plasma membrane-derived vesicles in the absence of potassium oxalate. These results suggest that relaxation of smooth muscle by papaverine is related to a cyclic AMP-independent mechanism as well as to a mechanism mediated via cyclic AMP.

KCl stimulation increases norepinephrine transporter function in PC12 cells.

PubMed

Mandela, Prashant; Ordway, Gregory A

2006-09-01

The norepinephrine transporter (NET) plays a pivotal role in terminating noradrenergic signaling and conserving norepinephrine (NE) through the process of re-uptake. Recent evidence suggests a close association between NE release and regulation of NET function. The present study evaluated the relationship between release and uptake, and the cellular mechanisms that govern these processes. KCl stimulation of PC12 cells robustly increased [3H]NE uptake via the NET and simultaneously increased [3H]NE release. KCl-stimulated increases in uptake and release were dependent on Ca2+. Treatment of cells with phorbol-12-myristate-13-acetate (PMA) or okadaic acid decreased [3H]NE uptake but did not block KCl-stimulated increases in [3H]NE uptake. In contrast, PMA increased [3H]NE release and augmented KCl-stimulated release, while okadaic acid had no effects on release. Inhibition of Ca2+-activated signaling cascades with KN93 (a Ca2+ calmodulin-dependent kinase inhibitor), or ML7 and ML9 (myosin light chain kinase inhibitors), reduced [3H]NE uptake and blocked KCl-stimulated increases in uptake. In contrast, KN93, ML7 and ML9 had no effect on KCl-stimulated [3H]NE release. KCl-stimulated increases in [3H]NE uptake were independent of transporter trafficking to the plasma membrane. While increases in both NE release and uptake mediated by KCl stimulation require Ca2+, different intracellular mechanisms mediate these two events.

Foliar uptake of radiocaesium from irrigation water by paddy rice (Oryza sativa): an overlooked pathway in contaminated environments.

PubMed

Uematsu, Shinichiro; Vandenhove, Hildegarde; Sweeck, Lieve; Hees, May Van; Wannijn, Jean; Smolders, Erik

2017-04-01

Flooded (paddy) rice (Oryza sativa) can take up ions from the irrigation water by foliar uptake via the exposed stem base. We hypothesised that the stem base uptake of radiocaesium (RCs) is a pathway for rice grown in RCs-contaminated environments. We developed a bi-compartmental device which discriminates the stem base from root RCs uptake from solutions, thereby using RCs isotopes ( 137 Cs and 134 Cs) with < 2% solution leak between the compartments. Radiocaesium uptake was linear over time (0-24 h). Radiocaesium uptake to the entire plant, expressed per dry weight of the exposed parts, was sixfold higher for the roots than for the exposed stem base. At equal RCs concentrations in both compartments, the exposed stem base and root uptake contributed almost equally to the total shoot RCs concentrations. Reducing potassium supply to the roots not only increased the root RCs uptake but also increased RCs uptake by the stem base. This study was the first to experimentally demonstrate active and internally regulated RCs uptake by the stem base of rice. Scenario calculations for the Fukushima-affected area predict that RCs in irrigation water could be an important source of RCs in rice as indirectly suggested from field data. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Comparison of in vitro fluoride uptake from whitening toothpastes and a conventional toothpaste in demineralised enamel.

PubMed

Altenburger, Markus J; Bernhart, Jasmin; Schicha, Thurid D; Wrbas, Karl-Thomas; Hellwig, Elmar

2010-01-01

Studies on the compatibility of abrasives and fluoride compounds deal exclusively with fluoride uptake and remineralization after storing the enamel specimens in a toothpaste-saliva mixture. The influence of brushing on the fluoride uptake when highly abrasive toothpastes are used has hardly been investigated so far. The aim of the present study was to investigate fluoride uptake in initially demineralised dental enamel after storage in, or brushing with, whitening toothpaste slurries, compared to a conventional toothpaste. For this purpose two widely available whitening toothpastes with ionically bound fluoride (sodium fluoride NaF), two with covalently-bound fluoride toothpastes (sodium monofluorophosphate, NaMFP) and a conventional amine fluoride toothpaste (AmF) were compared. The fluoride uptake after use of the AmF toothpaste was shown to be statistically significantly higher than that after application of the NaF toothpastes, which in turn was statistically significantly higher than the uptake resulting from NaMFP application. The fluoride uptake was slightly higher when the enamel samples were brushed with NaF toothpaste, rather than just stored in the respective toothpaste slurry. Brushing with highly abrasive toothpastes did not negatively influence fluoride uptake in demineralised dental enamel. The ionic form of the fluoride in toothpastes appears to be critical for increased fluoride uptake. The acidic components of the AmF toothpaste improved fluoride uptake compared to alkaline NaF toothpastes.

Hydrogen Peroxide-Dependent Uptake of Iodine by Marine Flavobacteriaceae Bacterium Strain C-21▿

PubMed Central

Amachi, Seigo; Kimura, Koh; Muramatsu, Yasuyuki; Shinoyama, Hirofumi; Fujii, Takaaki

2007-01-01

The cells of the marine bacterium strain C-21, which is phylogenetically closely related to Arenibacter troitsensis, accumulate iodine in the presence of glucose and iodide (I−). In this study, the detailed mechanism of iodine uptake by C-21 was determined using a radioactive iodide tracer, 125I−. In addition to glucose, oxygen and calcium ions were also required for the uptake of iodine. The uptake was not inhibited or was only partially inhibited by various metabolic inhibitors, whereas reducing agents and catalase strongly inhibited the uptake. When exogenous glucose oxidase was added to the cell suspension, enhanced uptake of iodine was observed. The uptake occurred even in the absence of glucose and oxygen if hydrogen peroxide was added to the cell suspension. Significant activity of glucose oxidase was found in the crude extracts of C-21, and it was located mainly in the membrane fraction. These findings indicate that hydrogen peroxide produced by glucose oxidase plays a key role in the uptake of iodine. Furthermore, enzymatic oxidation of iodide strongly stimulated iodine uptake in the absence of glucose. Based on these results, the mechanism was considered to consist of oxidation of iodide to hypoiodous acid by hydrogen peroxide, followed by passive translocation of this uncharged iodine species across the cell membrane. Interestingly, such a mechanism of iodine uptake is similar to that observed in iodine-accumulating marine algae. PMID:17933915

Association of vascular fluoride uptake with vascular calcification and coronary artery disease.

PubMed

Li, Yuxin; Berenji, Gholam R; Shaba, Wisam F; Tafti, Bashir; Yevdayev, Ella; Dadparvar, Simin

2012-01-01

The feasibility of a fluoride positron emission tomography/computed tomography (PET/CT) scan for imaging atherosclerosis has not been well documented. The purpose of this study was to assess fluoride uptake of vascular calcification in various major arteries, including coronary arteries. We retrospectively reviewed the imaging data and cardiovascular history of 61 patients who received whole-body sodium [¹⁸F]fluoride PET/CT studies at our institution from 2009 to 2010. Fluoride uptake and calcification in major arteries, including coronary arteries, were analyzed by both visual assessment and standardized uptake value measurement. Fluoride uptake in vascular walls was demonstrated in 361 sites of 54 (96%) patients, whereas calcification was observed in 317 sites of 49 (88%) patients. Significant correlation between fluoride uptake and calcification was observed in most of the arterial walls, except in those of the abdominal aorta. Fluoride uptake in coronary arteries was demonstrated in 28 (46%) patients and coronary calcifications were observed in 34 (56%) patients. There was significant correlation between history of cardiovascular events and presence of fluoride uptake in coronary arteries. The coronary fluoride uptake value in patients with cardiovascular events was significantly higher than in patients without cardiovascular events. sodium [¹⁸F]fluoride PET/CT might be useful in the evaluation of the atherosclerotic process in major arteries, including coronary arteries. An increased fluoride uptake in coronary arteries may be associated with an increased cardiovascular risk.

Intervention to lower anxiety of 18F-FDG PET/CT patients by use of audiovisual imagery during the uptake phase before imaging.

PubMed

Vogel, Wouter V; Valdés Olmos, Renato A; Tijs, Tim J W; Gillies, Murray F; van Elswijk, Gijs; Vogt, Juergen

2012-06-01

Many patients referred for PET suffer from anxiety, possibly affecting the workflow and patient experience. In addition, patient anxiety may affect image quality through uptake of (18)F-FDG in muscles or brown adipose tissue (BAT).This study investigated the effects of a nonpharmacologic intervention-the use of audiovisual imagery in the PET uptake room-on patient anxiety and false-positive uptake of (18)F-FDG (in muscles and BAT). A 2-stage study was conducted on 101 patients. The cohort undergoing the intervention included 51 patients. The first stage (n = 35) included physiologic measurements (cardiovascular activity, muscular activity, skin conductance, and cortisol), a state anxiety questionnaire, and visual evaluation of (18)F-FDG uptake in muscles and BAT; the second stage (n = 66) included only the state anxiety questionnaire and the (18)F-FDG uptake evaluation. Throughout the stay in the uptake room, a significant decrease in overall anxiety was found, together with several other significant changes in patient physiology. In the cohort with audiovisual intervention, however, the decrease in patient anxiety was significantly larger. The cohort with intervention also showed significantly lower (18)F-FDG uptake in BAT but not in muscles. The investigated audiovisual intervention helps to lower patient anxiety in the PET uptake room and can lower false-positive (18)F-FDG uptake in BAT.

Adenosine uptake by the isolated epithelium of guine pig jejunum.

PubMed

Kolassa, N; Stengg, R; Turnheim, K

1977-10-01

The uptake of [8-14C]adenosine by the isolated epithelium of guinea pig jejunum was faster than that of inosine, hypoxanthine, or adenine. The initial velocity of adenosine uptake from both the luminal and the antiluminal side of the epithelium exhibited saturation kinetics. The apparent Km, V, and passive permeability of luminal adenosine uptake were all lower than the corresponding values of antiluminal uptake. p-Nitrobenzyl-thioguanosine inhibited adenosine uptake from both the luminal and the antiluminal side, whilst hexobendine decreased the uptake only from the antiluminal side of the epithelium. The results suggest that adenosine enters the intestinal epithelium by a carrier-mediated process in addition to passive diffusion. The antiluminal transport system for adenosine seems similar to that of other tissues with respect to hexobendine inhibition; the luminal transport mechanism, however, exhibits different properties, being insensitive to hexobendine.

Diffusion Limitations in Root Uptake of Cadmium and Zinc, But Not Nickel, and Resulting Bias in the Michaelis Constant1[W][OA

PubMed Central

Degryse, Fien; Shahbazi, Afsaneh; Verheyen, Liesbeth; Smolders, Erik

2012-01-01

It has long been recognized that diffusive boundary layers affect the determination of active transport parameters, but this has been largely overlooked in plant physiological research. We studied the short-term uptake of cadmium (Cd), zinc (Zn), and nickel (Ni) by spinach (Spinacia oleracea) and tomato (Lycopersicon esculentum) in solutions with or without metal complexes. At same free ion concentration, the presence of complexes, which enhance the diffusion flux, increased the uptake of Cd and Zn, whereas Ni uptake was unaffected. Competition effects of protons on Cd and Zn uptake were observed only at a very large degree of buffering, while competition of magnesium ions on Ni uptake was observed even in unbuffered solutions. These results strongly suggest that uptake of Cd and Zn is limited by diffusion of the free ion to the roots, except at very high degree of solution buffering, whereas Ni uptake is generally internalization limited. All results could be well described by a model that combined a diffusion equation with a competitive Michaelis-Menten equation. Direct uptake of the complex was estimated to be a major contribution only at millimolar concentrations of the complex or at very large ratios of complex to free ion concentration. The true Km for uptake of Cd2+ and Zn2+ was estimated at <5 nm, three orders of magnitude smaller than the Km measured in unbuffered solutions. Published Michaelis constants for plant uptake of Cd and Zn likely strongly overestimate physiological ones and should not be interpreted as an indicator of transporter affinity. PMID:22864584

Uptake of (/sup 3/H)serotonin into plasma membrane vesicles from mouse cerebral cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Reilly, C.A.; Reith, M.E.A.

1988-05-05

Preparations of plasma membrane vesicles were used as a tool to study the properties of the serotonin transporter in the central nervous system. The vesicles were obtained after hypotonic shock of synaptosomes purified from mouse cerebral cortex. Uptake of (/sup 3/H)serotonin had a Na/sup +/-dependent and Na/sup +/-independent component. The Na/sup +/-dependent uptake was inhibited by classical blockers of serotonin uptake and had a K/sub m/ of 63-180 nM, and a V/sub max/ of 0.1-0.3 pmol mg/sup -1/ s/sup -1/ at 77 mM Na/sup +/. The uptake required the presence of external Na/sup +/ and internal K/sup +/. Replacement ofmore » Cl/sup -/ by other anions (NO/sub 2//sup -/, S/sub 2/O/sub 3//sup 2 -/) reduced uptake appreciably. Gramicidin prevented uptake. Although valinomycin increased uptake somewhat, the membrane potential per se could not drive uptake because no uptake was observed when a membrane potential was generated by the SCN/sup -/ ion in the absence of internal K/sup +/ and with equal (Na/sup +/) inside and outside. The increase of uptake as a function of (Na/sup +/) indicated a K/sub m/ for Na/sup +/ of 118 mM and a Hill number of 2.0, suggesting a requirement of two sodium ions for serotonin transport. The present results are accommodated very well by the model developed for porcine platelet serotonin transport except for the number of sodium ions that are required for transport.« less

Long term trend and interannual variability of land carbon uptake—the attribution and processes

NASA Astrophysics Data System (ADS)

Fu, Zheng; Dong, Jinwei; Zhou, Yuke; Stoy, Paul C.; Niu, Shuli

2017-01-01

Ecosystem carbon (C) uptake in terrestrial ecosystems has increased over the past five decades, but with large interannual variability (IAV). However, we are not clear on the attribution and the processes that control the long-term trend and IAV of land C uptake. Using atmospheric inversion net ecosystem exchange (NEE) data, we quantified the trend and IAV of NEE across the globe, the Northern Hemisphere (NH), and the Southern Hemisphere (SH), and decomposed NEE into carbon uptake amplitude and duration during each year from 1979-2013. We found the NH rather than the SH determined the IAV, while both hemispheres contributed equivalently to the global NEE trend. Different ecosystems in the NH and SH had differential relative contributions to their trend and IAV. The long-term trends of increased C uptake across the globe and the SH were attributed to both extended duration and increasing amplitude of C uptake. The shortened duration of uptake in the NH partly offsets the effects of increased NEE amplitude, making the net C uptake trend the same as that of the SH. The change in NEE IAV was also linked to changes in the amplitude and duration of uptake, but they worked in different ways in the NH, SH and globe. The fundamental attributions of amplitude and duration of C uptake revealed in this study are helpful to better understand the mechanisms underlying the trend and IAV of land C uptake. Our findings also suggest the critical roles of grassland and croplands in the NH in contributing to the trend and IAV of land C uptake.

Cysteine 96 of Ntcp is responsible for NO-mediated inhibition of taurocholate uptake.

PubMed

Ramasamy, Umadevi; Anwer, M Sawkat; Schonhoff, Christopher M

2013-10-01

The Na(+) taurocholate (TC) cotransporting polypeptide Ntcp/NTCP mediates TC uptake across the sinusoidal membrane of hepatocytes. Previously, we demonstrated that nitric oxide (NO) inhibits TC uptake through S-nitrosylation of a cysteine residue. Our current aim was to determine which of the eight cysteine residues of Ntcp is responsible for NO-mediated S-nitrosylation and inhibition of TC uptake. Thus, we tested the effect of NO on TC uptake in HuH-7 cells transiently transfected with cysteine-to-alanine mutant Ntcp constructs. Of the eight mutants tested, only C44A Ntcp displayed decreased total and plasma membrane (PM) levels that were also reflected in decreased TC uptake. C266A Ntcp showed a decrease in TC uptake that was not explained by a decrease in total expression or PM localization, indicating that C266 is required for optimal uptake. We speculated that NO would target C266 since a previous report had shown the thiol reactive compound [2-(trimethylammonium) ethyl] methanethiosulfonate bromide (MTSET) inhibits TC uptake by wild-type NTCP but not by C266A NTCP. We confirmed that MTSET targets C266 of Ntcp, but, surprisingly, we found that C266 was not responsible for NO-mediated inhibition of TC uptake. Instead, we found that C96 was targeted by NO since C96A Ntcp was insensitive to NO-mediated inhibition of TC uptake. We also found that wild-type but not C96A Ntcp is S-nitrosylated by NO, suggesting that C96 is important in regulating Ntcp function in response to elevated levels of NO.

Nitric oxide-mediated inhibition of taurocholate uptake involves S-nitrosylation of NTCP.

PubMed

Schonhoff, Christopher M; Ramasamy, Umadevi; Anwer, M Sawkat

2011-02-01

The sodium-taurocholate (TC) cotransporting polypeptide (NTCP) facilitates bile formation by mediating sinusoidal Na(+)-TC cotransport. During sepsis-induced cholestasis, there is a decrease in NTCP-dependent uptake of bile acids and an increase in nitric oxide (NO) levels in hepatocytes. In rat hepatocytes NO inhibits Na(+)-dependent uptake of taurocholate. The aim of this study was to extend these findings to human NTCP and to further investigate the mechanism by which NO inhibits TC uptake. Using a human hepatoma cell line stably expressing NTCP (HuH-NTCP), we performed experiments with the NO donors sodium nitroprusside and S-nitrosocysteine and demonstrated that NO inhibits TC uptake in these cells. Kinetic analyses revealed that NO significantly decreased the V(max) but not the K(m) of TC uptake by NTCP, indicating noncompetitive inhibition. NO decreased the amount of NTCP in the plasma membrane, providing a molecular mechanism for the noncompetitive inhibition of TC uptake. One way that NO can modify protein function is through a posttranslational modification known as S-nitrosylation: the binding of NO to cysteine thiols. Using a biotin switch technique we observed that NTCP is S-nitrosylated under conditions in which NO inhibits TC uptake. Moreover, dithiothreitol reversed NO-mediated inhibition of TC uptake and S-nitrosylation of NTCP, indicating that NO inhibits TC uptake via modification of cysteine thiols. In addition, NO treatment led to a decrease in Ntcp phosphorylation. Taken together these results indicate that the inhibition of TC uptake by NO involves S-nitrosylation of NTCP.

Cysteine 96 of Ntcp is responsible for NO-mediated inhibition of taurocholate uptake

PubMed Central

Ramasamy, Umadevi; Anwer, M. Sawkat

2013-01-01

The Na+ taurocholate (TC) cotransporting polypeptide Ntcp/NTCP mediates TC uptake across the sinusoidal membrane of hepatocytes. Previously, we demonstrated that nitric oxide (NO) inhibits TC uptake through S-nitrosylation of a cysteine residue. Our current aim was to determine which of the eight cysteine residues of Ntcp is responsible for NO-mediated S-nitrosylation and inhibition of TC uptake. Thus, we tested the effect of NO on TC uptake in HuH-7 cells transiently transfected with cysteine-to-alanine mutant Ntcp constructs. Of the eight mutants tested, only C44A Ntcp displayed decreased total and plasma membrane (PM) levels that were also reflected in decreased TC uptake. C266A Ntcp showed a decrease in TC uptake that was not explained by a decrease in total expression or PM localization, indicating that C266 is required for optimal uptake. We speculated that NO would target C266 since a previous report had shown the thiol reactive compound [2-(trimethylammonium) ethyl] methanethiosulfonate bromide (MTSET) inhibits TC uptake by wild-type NTCP but not by C266A NTCP. We confirmed that MTSET targets C266 of Ntcp, but, surprisingly, we found that C266 was not responsible for NO-mediated inhibition of TC uptake. Instead, we found that C96 was targeted by NO since C96A Ntcp was insensitive to NO-mediated inhibition of TC uptake. We also found that wild-type but not C96A Ntcp is S-nitrosylated by NO, suggesting that C96 is important in regulating Ntcp function in response to elevated levels of NO. PMID:23886862

Effects of polyamine inhibitors on zinc uptake by COMMA-1D mammary epithelial cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, J.C.; Haedrich, L.H.

1991-03-15

Zn uptake or transport is stimulated by glucocorticoids in many types of epithelial cells, including the COMMA-1D mouse mammary cell line. The current objective was to determine whether polyamines also mediate glucocorticoid stimulation of Zn-uptake. Initially, cells grown in lactogenic hormone supplemented-media had approximately 65% greater {sup 65}Zn-uptake over 24 h than cells in nonsupplemented growth media (GM). {sup 65}Zn-uptake from HM with 10{sup {minus}5}M methylglyoxal-bis(guanylhydrazone) (MGBG) (s-adenosyl-methionine decarboxylase inhibitor to block polyamine synthesis) added was less than from GM. Exogenous spermidine added to the MGBG-HM media increased {sup 65}Zn-uptake. However, up to 10mM difluoromethylornithine (DFMO), a more specific inhibitormore » of sperimidine synthesis, had no significant effect on 24-h {sup 65}Zn-uptake by cells in HM. In GM, DFMO caused a slight dose-dependent decrease in {sup 65}Zn-uptake over the range 10{sup {minus}6} to 5 {times} 10{sup 3}M. Also, with 8 h of incubation, DFMO tended to decrease {sup 65}Zn-uptake in HM-stimulated cells. These data cannot yet distinguish between the possibilities that DFMO is inactivated during the 24-h incubation or that the dramatic effects of MGBG on {sup 65}Zn-uptake in these mammary-derived cells is not related to its inhibition of polyamine synthesis. Because COMMA-1D cells alter Zn uptake in response to lactogenic hormones and MGBG, the model system is suitable for further studies of the mechanisms of zinc transport in epithelia.« less

Short-term and long-term ethanol administration inhibits the placental uptake and transport of valine in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patwardhan, R.V.; Schenker, S.; Henderson, G.I.

1981-08-01

Ethanol ingestion during pregnancy causes a pattern of fetal/neonatal dysfunction called the FAS. The effects of short- and long-term ethanol ingestion on the placental uptake and maternal-fetal transfer of valine were studied in rats. The in vivo placental uptake and fetal uptake were estimated after injection of 0.04 micromol of /sub 14/C-valine intravenously on day 20 of gestation in Sprague-Dawley rats. Short-term ethanol ingestion (4 gm/kg) caused a significant reduction in the placental uptake of /sub 14/C-valine by 33%, 60%, and 30%, and 31% at 2.5, 5, 10, and 15 min after valine administration, respectively (p less than 0.01), andmore » a similar significant reduction occurred in the fetal uptake of /sub 14/C-valine (p less than 0.01). Long-term ethanol ingestion prior to and throughout gestation resulted in a 47% reduction in placental valine uptake (p less than 0.01) and a 46% reduction in fetal valine uptake (p less than 0.01). Long-term ethanol feeding from day 4 to day 20 of gestation caused a 32% reduction in placental valine uptake (p less than 0.01) and a 26% reduction in fetal valine uptake (p less than 0.01). We conclude that both short- and long-term ingestion of ethanol inhibit the placental uptake and maternal-fetal transfer of an essential amino acid--valine. An alteration of placental function may contribute to the pathogenesis of the FAS.« less

21 CFR 886.1670 - Ophthalmic isotope uptake probe.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to measure...

21 CFR 886.1670 - Ophthalmic isotope uptake probe.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to measure...

21 CFR 886.1670 - Ophthalmic isotope uptake probe.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic isotope uptake probe. 886.1670 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1670 Ophthalmic isotope uptake probe. (a) Identification. An ophthalmic isotope uptake probe is an AC-powered device intended to measure...

21 CFR 868.1730 - Oxygen uptake computer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by a...

21 CFR 868.1730 - Oxygen uptake computer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by a...

21 CFR 868.1730 - Oxygen uptake computer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by a...

21 CFR 868.1730 - Oxygen uptake computer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by a...

21 CFR 868.1730 - Oxygen uptake computer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Oxygen uptake computer. 868.1730 Section 868.1730...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1730 Oxygen uptake computer. (a) Identification. An oxygen uptake computer is a device intended to compute the amount of oxygen consumed by a...

21 CFR 892.1320 - Nuclear uptake probe.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by a...

21 CFR 892.1320 - Nuclear uptake probe.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nuclear uptake probe. 892.1320 Section 892.1320...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1320 Nuclear uptake probe. (a) Identification. A nuclear uptake probe is a device intended to measure the amount of radionuclide taken up by a...

Capturing Individual Uptake: Toward a Disruptive Research Methodology

ERIC Educational Resources Information Center

Bastian, Heather

2015-01-01

This article presents and illustrates a qualitative research methodology for studies of uptake. It does so by articulating a theoretical framework for qualitative investigations of uptake and detailing a research study designed to invoke and capture students' uptakes in a first-year writing classroom. The research design sought to make uptake…

Study on kinetics of glucose uptake by some species of plankton

NASA Astrophysics Data System (ADS)

Li, Wenquan; Wang, Xian; Zhang, Yaohua

1993-03-01

The rates of glucose uptake by some species of plankton were determined by3H-glucose tracer method. Experimental results indicated that the observed glucose uptake at natural seawater concentrations by Platymonas subcordiformis and Brachionus plicatilis was principally a metabolic process fitted with the Michaelis-Menten equation in the range of adaptive temperatures. Heterotrophic uptake by Platymonas subcordiformis was mainly dependent on diffusion at high glucose levels. The uptake by Brachionus plicatilis showed active transport even at high glucose levels, indicating its high heterotrophic activity. The uptake rate by Artemia salina was lower, and its V m/K ratio was lower than those of the other two species of plankton.

Melanosome uptake is associated with the proliferation and differentiation of keratinocytes.

PubMed

Choi, Hye-In; Sohn, Kyung-Cheol; Hong, Dong-Kyun; Lee, Young; Kim, Chang Deok; Yoon, Tae-Jin; Park, Jin Woon; Jung, Sunggyun; Lee, Jeung-Hoon; Lee, Young Ho

2014-01-01

Melanosomes are synthesized in melanocytes and transferred to neighboring keratinocytes. However, the associations of melanosome uptake with the proliferation and differentiation of keratinocytes are not fully understood. We examined the associations of melanosome uptake with keratinocyte differentiation and proliferation. SV40T-transformed human epidermal keratinocytes (SV-HEKs) were treated with isolated melanosomes. The effects of melanosome uptake on the proliferation and differentiation of the keratinocytes were analyzed by Western blotting and flow cytometry. The relationship between melanosome uptake and keratinocyte differentiation status was verified by determining the melanin content in the cells. Melanosomes reduced the proliferation of SV-HEKs in a dose-dependent manner, but did not induce differentiation. Melanosome uptake was higher in differentiating keratinocytes compared to non-differentiating keratinocytes, and inhibited significantly by PAR-2 inhibitor. Melanosomes inhibit keratinocyte proliferation. Moreover, melanosome uptake is influenced by keratinocyte differentiation status, being highest in mid-stage differentiating keratinocytes in a PAR-2 dependent manner.

Influenza Vaccine Uptake, Hand Hygiene Practices, and Perceived Barriers in Decision Making.

PubMed

Stedman-Smith, Maggie; Kingsbury, Diana M; Dubois, Cathy L Z; Grey, Scott F

2017-01-01

The annual costs of influenza are in the billions of dollars, with employers bearing substantial burdens. Yet, influenza vaccine uptake is sub-optimal. A random survey was administered to employees at a Midwestern public university using mixed quantitative and qualitative methods to identify the rate, characteristics, and barriers of self-reported flu vaccine uptake during March-April of 2012. The lowest uptake was among adults, ages 18 to 49 (29.8%), even though they are included in universal recommendations. Multiple regression analysis adjusted for demographic confounders showed an increase in self-identified protective hand hygiene behavior among those who reported influenza vaccine uptake compared with those who did not. Qualitative thematic analysis revealed contextual accounts of why vaccine uptake was declined including structural, perceptual, and knowledge barriers. Implementation and evaluation of novel multicomponent worksite vaccine interventions tailored to reach young and middle-aged employees including utilization of risk communication is needed to facilitate increased uptake.

Cell uptake survey of pegylated nanographene oxide.

PubMed

Vila, M; Portolés, M T; Marques, P A A P; Feito, M J; Matesanz, M C; Ramírez-Santillán, C; Gonçalves, G; Cruz, S M A; Nieto, A; Vallet-Regi, M

2012-11-23

Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml(-1) pegylated GO solutions. GO uptake kinetics revealed differences in the agent's uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy.

Isopycnal mixing by mesoscale eddies significantly impacts oceanic anthropogenic carbon uptake

NASA Astrophysics Data System (ADS)

Gnanadesikan, Anand; Pradal, Marie-Aude; Abernathey, Ryan

2015-06-01

Anthropogenic carbon dioxide uptake varies across Earth System Models for reasons that have remained obscure. When varied within a single model, the lateral eddy mixing coefficient ARedi produces a range of uptake similar to the modeled range. The highest uptake, resulting from a simulation with a constant ARedi of 2400 m2/s, simulates 15% more historical carbon uptake than a model with ARedi = 400 m2/s. A sudden doubling in carbon dioxide produces a 21% range in carbon uptake across the models. Two spatially dependent representations of ARedi produce uptake that lies in the middle of the range of constant values despite predicting very large values in the subtropical gyres. One-dimensional diffusive models of the type used for integrated assessments can be fit to the simulations, with ARedi accounting for a substantial fraction of the effective vertical diffusion. Such models, however, mask significant regional changes in stratification and biological carbon storage.

Nitrogen uptake by wheat seedlings, interactive effects of four nitrogen sources: NO3-, NO2-, NH4+, and urea

NASA Technical Reports Server (NTRS)

Criddle, R. S.; Ward, M. R.; Huffaker, R. C.

1988-01-01

The net influx (uptake) rates of NO3-, NH4+, NO2-, and urea into roots of wheat (Triticum aestivum cv Yecora Rojo) seedlings from complete nutrient solutions containing all four compounds were monitored simultaneously. Although urea uptake was too slow to monitor, its presence had major inhibitory effects on the uptake of each of the other compounds. Rates of NO3-, NH4+, and NO2- uptake depended in a complex fashion on the concentration of all four N compounds. Equations were developed which describe the uptake rates of each of the compounds, and of total N, as functions of concentrations of all N sources. Contour plots of the results show the interactions over the range of concentrations employed. The coefficients of these equations provide quantitative values for evaluating primary and interactive effects of each compound on N uptake.

Polyphenol-rich beverages enhance zinc uptake and metallothionein expression in Caco-2 cells.

PubMed

Sreenivasulu, Kilari; Raghu, Pullakhandam; Nair, K Madhavan

2010-05-01

The effect of red wine (RW), red grape juice (RGJ), green tea (GT), and representative polyphenols on Caco-2 cell (65)Zn uptake was explored. RW, RGJ, and GT enhanced the uptake of zinc from rice matrix. Fractionation of RW revealed that enhancing activity of zinc uptake was exclusively resided in the polyphenol fraction. Among the polyphenols tested, only tannic acid and quercitin stimulated the uptake of zinc while others did not influence the uptake. In tune with these results, only tannic acid and quercitin competed with zinquin (a zinc selective fluorophore) for zinc in vitro. Although all the polyphenols tested appear to enhance the expression of metallothionein (MT), the induction was higher with tannic acid, quercitin, and RW extract. Furthermore, phytic acid abrogated the tannic acid-induced MT expression. These results suggest that polyphenol-rich beverages, tannic acid, and quercitin bind and stimulate the zinc uptake and MT expression in Caco-2 cells.

Distinct Akt phosphorylation states are required for insulin regulated Glut4 and Glut1-mediated glucose uptake.

PubMed

Beg, Muheeb; Abdullah, Nazish; Thowfeik, Fathima Shazna; Altorki, Nasser K; McGraw, Timothy E

2017-06-07

Insulin, downstream of Akt activation, promotes glucose uptake into fat and muscle cells to lower postprandial blood glucose, an enforced change in cellular metabolism to maintain glucose homeostasis. This effect is mediated by the Glut4 glucose transporter. Growth factors also enhance glucose uptake to fuel an anabolic metabolism required for tissue growth and repair. This activity is predominantly mediated by the Glut1. Akt is activated by phosphorylation of its kinase and hydrophobic motif (HM) domains. We show that insulin-stimulated Glut4-mediated glucose uptake requires PDPK1 phosphorylation of the kinase domain but not mTORC2 phosphorylation of the HM domain. Nonetheless, an intact HM domain is required for Glut4-mediated glucose uptake. Whereas, Glut1-mediated glucose uptake also requires mTORC2 phosphorylation of the HM domain, demonstrating both phosphorylation-dependent and independent roles of the HM domain in regulating glucose uptake. Thus, mTORC2 links Akt to the distinct physiologic programs related to Glut4 and Glut1-mediated glucose uptake.

Thrombin-induced glucose transport via Src–p38 MAPK pathway in vascular smooth muscle cells

PubMed Central

Kanda, Yasunari; Watanabe, Yasuhiro

2005-01-01

Thrombin is a mitogen for vascular smooth muscle cells (VSMC) and has been implicated in the development in atherosclerosis. However, little is known about the role of thrombin in glucose transport in VSMC. In this study, we examined the effect of thrombin on glucose uptake in rat A10 VSMC. We found that thrombin induced glucose uptake in a dose-dependent manner while hirudin, a potent thrombin inhibitor, prevented glucose uptake in the cells. PP2, a selective inhibitor of Src, prevented the thrombin-induced glucose uptake, but did not affect insulin-induced uptake. We also examined whether mitogen-activated protein kinase (MAPK) inhibitors influenced thrombin-induced glucose uptake. The p38 MAPK inhibitor (SB203580) inhibited thrombin-induced glucose uptake, but the MEK inhibitor (PD98059) did not. In contrast to thrombin, SB203580 did not affect insulin-induced glucose uptake. Furthermore, thrombin failed to translocate the insulin-sensitive glucose transporter GLUT4. These findings suggest that thrombin stimulates glucose transport via Src and subsequent p38 MAPK activation in VSMC. PMID:15951827

Solute-specific scaling of inorganic nitrogen and phosphorus uptake in streams

NASA Astrophysics Data System (ADS)

Hall, R. O., Jr.; Baker, M. A.; Rosi-Marshall, E. J.; Tank, J. L.; Newbold, J. D.

2013-11-01

Stream ecosystem processes such as nutrient cycling may vary with stream position in the network. Using a scaling approach, we examined the relationship between stream size and nutrient uptake length, which represents the mean distance that a dissolved solute travels prior to removal from the water column. Ammonium (NH4+) uptake length increased proportionally with stream size measured as specific discharge (discharge/stream width) with a scaling exponent = 1.01. In contrast, uptake lengths for nitrate (NO3-) and soluble reactive phosphorus (SRP) increased more rapidly than increases in specific discharge (scaling exponents = 1.19 for NO3- and 1.35 for SRP). Additionally, the ratio of inorganic nitrogen (N) uptake length to SRP uptake length declined with stream size; there was relatively lower demand for SRP compared to N as stream size increased. Finally, we related the scaling of uptake length with specific discharge to that of stream length using Hack's law and downstream hydraulic geometry. Ammonium uptake length increased less than proportionally with distance from the headwaters, suggesting a strong role for larger streams and rivers in regulating nutrient transport.

Cold tuberculous abscess identified by FDG PET.

PubMed

Yago, Yuzo; Yukihiro, Masashi; Kuroki, Hirofumi; Katsuragawa, Yuzo; Kubota, Kazuo

2005-09-01

We report FDG PET of two cases of cold abscess due to Mycobacterium tuberculosis. Case 1 had colon cancer; FDG PET showed high FDG uptake in the colon lesion and low uptake in the inguinal lesion. The latter was a tuberculous cold abscess confirmed by CT/MRI and biopsy. Case 2 received radiotherapy for lung cancer and presented with suspected vertebral metastasis. Further studies revealed tuberculosis of the vertebra and a tuberculous cold abscess in the iliopsoas muscle. FDG PET showed moderate uptake in the third lumbar spine and low uptake in the abscess center of iliopsoas lesion. Both tuberculous cold abscesses showed moderate FDG uptake in the capsule and low uptake in the center. These features are unique compared with non-tuberculous abscess and typical tuberculosis lesions, which are characterized by high FDG uptake. Pathologically, tuberculous cold abscess is not accompanied by active inflammatory reaction. Our findings suggested that the FDG uptake by tuberculous lesion varies according to the grade of inflammatory activity. The new diagnostic features of tuberculous cold abscess may be useful in the evaluation of such lesions by FDG PET.

Differences in dissolved cadmium and zinc uptake among stream insects: Mechanistic explanations

USGS Publications Warehouse

Buchwalter, D.B.; Luoma, S.N.

2005-01-01

This study examined the extent to which dissolved Cd and Zn uptake rates vary in several aquatic insect taxa commonly used as indicators of ecological health. We further attempted to explain the mechanisms underlying observed differences. By comparing dissolved Cd and Zn uptake rates in several aquatic insect species, we demonstrated that species vary widely in these processes. Dissolved uptake rates were not related to gross morphological features such as body size or gill size-features that influence water permeability and therefore have ionoregulatory importance. However, finer morphological features, specifically, the relative numbers of ionoregulatory cells (chloride cells), appeared to be related to dissolved metal uptake rates. This observation was supported by Michaelis-Menten type kinetics experiments, which showed that dissolved Cd uptake rates were driven by the numbers of Cd transporters and not by the affinities of those transporters to Cd. Calcium concentrations in exposure media similarly affected Cd and Zn uptake rates in the caddisfly Hydropsyche californica. Dissolved Cd and Zn uptake rates strongly co-varied among species, suggesting that these metals are transported by similar mechanisms.

Effect of grazing on methane uptake from Eurasian steppe of China.

PubMed

Tang, Shiming; Zhang, Yujuan; Zhai, Xiajie; Wilkes, Andreas; Wang, Chengjie; Wang, Kun

2018-03-20

The effects of grazing on soil methane (CH 4 ) uptake in steppe ecosystems are important for understanding carbon sequestration and cycling because the role of grassland soil for CH 4 uptake can have major impacts at the global level. Here, a meta-analysis of 27 individual studies was carried out to assess the response patterns of soil CH 4 uptake to grazing in steppe ecosystems of China. The weighted log response ratio was used to assess the effect size. We found that heavy grazing significantly depressed soil CH 4 uptake by 36.47%, but light and moderate grazing had no significant effects in grassland ecosystem. The response of grassland soil CH 4 uptake to grazing also was found to depend upon grazing intensity, grazing duration and climatic types. The increase in soil temperature and reduced aboveground biomass and soil moisture induced by heavy grazing may be the major regulators of the soil CH 4 uptake. These findings imply that grazing effects on soil CH 4 uptake are highly context-specific and that grazing in different grasslands might be managed differently to help mitigate greenhouse gas emissions.

Static magnetic field reduced exogenous oligonucleotide uptake by spermatozoa using magnetic nanoparticle gene delivery system

NASA Astrophysics Data System (ADS)

Katebi, Samira; Esmaeili, Abolghasem; Ghaedi, Kamran

2016-03-01

Spermatozoa could introduce exogenous oligonucleotides of interest to the oocyte. The most important reason of low efficiency of sperm mediated gene transfer (SMGT) is low uptake of exogenous DNA by spermatozoa. The aim of this study was to evaluate the effects of static magnetic field on exogenous oligonucleotide uptake of spermatozoa using magnetofection method. Magnetic nanoparticles (MNPs) associated with the labeled oligonucleotides were used to increase the efficiency of exogenous oligonucleotide uptake by rooster spermatozoa. We used high-field/high-gradient magnet (NdFeB) to enhance and accelerate exogenous DNA sedimentation at the spermatozoa surface. Flow cytometry analysis was performed to measure viability and percentage of exogenous oligonucleotide uptake by sperm. Flow cytometry analysis showed a significant increase in exogenous oligonucleotide uptake by rooster spermatozoa (P<0.001) when spermatozoa were incubated in exogenous oligonucleotide solution and MNPs. However, by applying static magnetic field during magnetofection method, a significant decrease in exogenous oligonucleotide uptake was observed (P<0.05). Findings of this study showed that MNPs were effective to increase exogenous oligonucleotide uptake by rooster spermatozoa; however unlike others studies, static magnetic field, was not only ineffective to enhance exogenous oligonucleotide uptake by rooster spermatozoa but also led to reduction in efficiency of magnetic nanoparticles in gene transfer.

Contribution of sediment fluxes and transformations to the summer nitrogen budget of an Upper Mississippi River backwater system

USGS Publications Warehouse

James, W.F.; Richardson, W.B.; Soballe, D.M.

2008-01-01

Routing nitrate through backwaters of regulated floodplain rivers to increase retention could decrease loading to nitrogen (N)-sensitive coastal regions. Sediment core determinations of N flux were combined with inflow-outflow fluxes to develop mass balance approximations of N uptake and transformations in a flow-controlled backwater of the Upper Mississippi River (USA). Inflow was the dominant nitrate source (>95%) versus nitrification and varied as a function of source water concentration since flow was constant. Nitrate uptake length increased linearly, while uptake velocity decreased linearly, with increasing inflow concentration to 2 mg l-1, indicating limitation of N uptake by loading. N saturation at higher inflow concentration coincided with maximum uptake capacity, 40% uptake efficiency, and an uptake length 2 times greater than the length of the backwater. Nitrate diffusion and denitrification in sediment accounted for 27% of the backwater nitrate retention, indicating that assimilation by other biota or denitrification on other substrates were the dominant uptake mechanisms. Ammonium export from the backwater was driven by diffusive efflux from the sediment. Ammonium increased from near zero at the inflow to a maximum mid-lake, then declined slightly toward the outflow due to uptake during transport. Ammonium export was small compared to nitrate retention. ?? 2007 Springer Science+Business Media B.V.

Chloride inhibition of nitrite uptake for non-teleost Actinopterygiian fishes.

PubMed

Boudreaux, Perry J; Ferrara, Allyse M; Fontenot, Quenton C

2007-06-01

Fish that transport environmental chloride with a gill uptake mechanism (gill epithelial Cl(-)/HCO(3)(-)cotransport exchange system), also transport nitrite into plasma through the same mechanism. Because of the relationship between nitrite uptake and the gill chloride uptake mechanism, nitrite uptake can provide insight regarding the method of chloride uptake for fish. This study was designed to determine if non-teleost fishes concentrate nitrite in their plasma, and to determine if chloride inhibits nitrite uptake in non-teleost fish. To determine if bowfin Amia calva, spotted gar Lepisosteus oculatus, alligator gar Atractosteus spatula, and paddlefish Polyodon spathula concentrate environmental nitrite in their plasma, individuals were exposed to concentrations of 0, 1, 10, or 100 mg/L nitrite-N. After exposure, all species had plasma nitrite-N concentrations greater than environmental levels. To determine if chloride inhibits nitrite uptake for spotted gar, alligator gar, and paddlefish, fish were exposed to 1 mg/L nitrite-N and 20 mg/L chloride as calcium chloride, or to 1 mg/L nitrite-N only. Chloride effectively prevented nitrite from being concentrated in the plasma of all species. It appears that non-teleost fish concentrate nitrite in their plasma via their chloride uptake mechanism and that this is an ancestral characteristic for teleost.

Enantio-selective molecular dynamics of (±)-o,p-DDT uptake and degradation in water-sediment system.

PubMed

Ali, Imran; Alharbi, Omar M L; Alothman, Zeid A; Alwarthan, Abdulrahman

2018-01-01

Enantio-selective molecular dynamics of (±)-o,p-DDT uptake and degradation in water-sediment system is described. Both uptake and degradation processes of (-)-o,p-DDT were slightly higher than (+)-o,p-DDT enantiomer. The optimized parameters for uptake were 7.0μgL -1 concentration of o,p-DDT, 60min contact time, 5.0pH, 6.0gL -1 amount of reverine sediment and 25°C temperature. The maximum degradation of both (-)- and (+)-o,p-DDT was obtained with 16 days, 0.4μgL -1 concentration of o,p-DDT, pH 7 and 35°C temperature. Both uptake and degraded process followed first order rate reaction. Thermodynamic parameters indicated exothermic nature of uptake and degradation processes. Both uptake and degradation were slightly higher for (-)-enantiomer in comparison to (+)-enantiomer of o,p-DDT. It was concluded that both uptake and degradation processes are responsible for the removal of o,p-DDT from nature but uptake plays a crucial role. The percentage degradations of (-)- and (+)-o,p-DDT were 30.1 and 29.5, respectively. This study may be useful to manage o,p-DDT contamination of our earth's ecosystem. Copyright © 2017. Published by Elsevier Inc.

Heme iron uptake by Caco-2 cells is a saturable, temperature sensitive and modulated by extracellular pH and potassium.

PubMed

Arredondo, Miguel; Kloosterman, Janneke; Núñez, Sergio; Segovia, Fabián; Candia, Valeria; Flores, Sebastián; Le Blanc, Solange; Olivares, Manuel; Pizarro, Fernando

2008-11-01

It is known that heme iron and inorganic iron are absorbed differently. Heme iron is found in the diet mainly in the form of hemoglobin and myoglobin. The mechanism of iron absorption remains uncertain. This study focused on the heme iron uptake by Caco-2 cells from a hemoglobin digest and its response to different iron concentrations. We studied the intracellular Fe concentration and the effect of time, K+ depletion, and cytosol acidification on apical uptake and transepithelial transport in cells incubated with different heme Fe concentrations. Cells incubated with hemoglobin-digest showed a lower intracellular Fe concentration than cells grown with inorganic Fe. However, uptake and transepithelial transport of Fe was higher in cells incubated with heme Fe. Heme Fe uptake had a low Vmax and Km as compared to inorganic Fe uptake and did not compete with non-heme Fe uptake. Heme Fe uptake was inhibited in cells exposed to K+ depletion or cytosol acidification. Heme oxygenase 1 expression increased and DMT1 expression decreased with higher heme Fe concentrations in the media. The uptake of heme iron is a saturable and temperature-dependent process and, therefore, could occur through a mechanism involving both a receptor and the endocytic pathway.

ATP-sensitive potassium channels participate in glucose uptake in skeletal muscle and adipose tissue.

PubMed

Miki, Takashi; Minami, Kohtaro; Zhang, Li; Morita, Mizuo; Gonoi, Tohru; Shiuchi, Tetsuya; Minokoshi, Yasuhiko; Renaud, Jean-Marc; Seino, Susumu

2002-12-01

ATP-sensitive potassium (K(ATP)) channels are known to be critical in the control of both insulin and glucagon secretion, the major hormones in the maintenance of glucose homeostasis. The involvement of K(ATP) channels in glucose uptake in the target tissues of insulin, however, is not known. We show here that Kir6.2(-/-) mice lacking Kir6.2, the pore-forming subunit of these channels, have no K(ATP) channel activity in their skeletal muscles. A 2-deoxy-[(3)H]glucose uptake experiment in vivo showed that the basal and insulin-stimulated glucose uptake in skeletal muscles and adipose tissues of Kir6.2(-/-) mice is enhanced compared with that in wild-type (WT) mice. In addition, in vitro measurement of glucose uptake indicates that disruption of the channel increases the basal glucose uptake in Kir6.2(-/-) extensor digitorum longus and the insulin-stimulated glucose uptake in Kir6.2(-/-) soleus muscle. In contrast, glucose uptake in adipose tissue, measured in vitro, was similar in Kir6.2(-/-) and WT mice, suggesting that the increase in glucose uptake in Kir6.2(-/-) adipocytes is mediated by altered extracellular hormonal or neuronal signals altered by disruption of the K(ATP) channels.

Factors affecting the oral uptake and translocation of polystyrene nanoparticles: histological and analytical evidence.

PubMed

Florence, A T; Hillery, A M; Hussain, N; Jani, P U

1995-01-01

Quantitative and qualitative evidence from our laboratories on the absorption and translocation of polystyrene latex nanoparticles both by histological (qualitative) and analytical measurement of levels of polystyrene (quantitative) is briefly reviewed in this paper. We have previously compared the uptake of nonionized polystyrene latex ranging in size from 50nm to 3 microns, and made some comparisons of uptake between carboxylated microspheres and nonionic systems, showing the lower uptake of the former through the lymphoid tissue of the gastrointestinal tract. Size is a key parameter, uptake increasing with decreasing particle diameter. Early evidence suggested that uptake is by way of the Peyer's patches and other elements of the gut associated lymphoid tissue (GALT). Adsorption of hydrophilic block-copolymers onto polystyrene markedly reduces the uptake by intestinal GALT. Modification of the surface with specific ligands such as by covalent attachment of tomato lectin molecules has indicated widespread uptake by non-GALT tissues, following their binding to and internalisation by enterocytes. The ability to decrease and increase uptake is clear evidence of a phenomenon which has the potential for further control to allow it to be exploited fully for drug or vaccine delivery. The evidence to date with nanoparticles as carriers systems for labile drugs such as proteins by the oral route remains to be substantiated.

Microscale characterization of dissolved organic matter production and uptake in marine microbial mat communities

NASA Technical Reports Server (NTRS)

Paerl, H. W.; Bebout, B. M.; Joye, S. B.; Des Marais, D. J.

1993-01-01

Intertidal marine microbial mats exhibited biologically mediated uptake of low molecular weight dissolved organic matter (DOM), including D-glucose, acetate, and an L-amino acid mixture at trace concentrations. Uptake of all compounds occurred in darkness, but was frequently enhanced under natural illumination. The photosystem 2 inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU) generally failed to inhibit light-stimulated DOM uptake. Occasionally, light plus DCMU-amended treatments led to uptake rates higher than light-incubated samples, possibly due to phototrophic bacteria present in subsurface anoxic layers. Uptake was similar with either 3H- or 14C-labeled substrates, indicating that recycling of labeled CO2 via photosynthetic fixation was not interfering with measurements of light-stimulated DOM uptake. Microautoradiographs showed a variety of pigmented and nonpigmented bacteria and, to a lesser extent, cyanobacteria and eucaryotic microalgae involved in light-mediated DOM uptake. Light-stimulated DOM uptake was often observed in bacteria associated with sheaths and mucilage surrounding filamentous cyanobacteria, revealing a close association of organisms taking up DOM with photoautotrophic members of the mat community. The capacity for dark- and light-mediated heterotrophy, coupled to efficient retention of fixed carbon in the mat community, may help optimize net production and accretion of mats, even in oligotrophic waters.

HISTOCHEMICAL STUDIES ON THE UPTAKE OF HORSERADISH PEROXIDASE BY RAT KIDNEY SLICES

PubMed Central

Miller, A. T.; Hale, D. M.; Alexander, K. D.

1965-01-01

When rat kidney slices were incubated in the presence of horseradish peroxidase, there was an energy-dependent uptake of the protein by the cells of the kidney tubules. The uptake was greatest in the proximal convoluted tubules and in the thick ascending limbs of the loops of Henle; it was abolished by cold, anoxia, 2,4-dinitrophenol, and fluoroacetate, and was more readily depressed by unfavorable metabolic conditions in the proximal convoluted tubules than in the thick ascending limbs. Protein uptake was inhibited when the kidney slices were incubated in electrolyte-free media. In sodium chloride solutions, uptake was reduced as sodium was progressively replaced by choline, and ouabain inhibited uptake in the proximal convoluted tubules, but not in the thick ascending limbs. To a limited extent, lithium could replace sodium in the incubation medium with no depression of peroxidase uptake. These results suggest that a sodium-stimulated, ouabain-sensitive ATPase may be involved in the uptake of protein by cells of the kidney tubule. The intracellular transport of peroxidase in cells of the proximal convoluted tubules was abolished by cold, anoxia, and 2,4-dinitrophenol, but it was not affected by concentrations of ouabain which inhibited the uptake of the protein. PMID:5884629

Variable phosphorus uptake rates and allocation across microbial groups in the oligotrophic Gulf of Mexico.

PubMed

Popendorf, Kimberly J; Duhamel, Solange

2015-10-01

Microbial uptake of dissolved phosphorus (P) is an important lever in controlling both microbial production and the fate and cycling of marine P. We investigated the relative role of heterotrophic bacteria and phytoplankton in P cycling by measuring the P uptake rates of individual microbial groups (heterotrophic bacteria and the phytoplankton groups Synechococcus, Prochlorococcus and picoeukaryotic phytoplankton) in the P-depleted Gulf of Mexico. Phosphorus uptake rates were measured using incubations with radiolabelled phosphate and adenosine triphosphate coupled with cell sorting flow cytometry. We found that heterotrophic bacteria were the dominant consumers of P on both a biomass basis and a population basis. Biovolume normalized heterotrophic bacteria P uptake rate per cell (amol P μm(-3) h(-1)) was roughly an order of magnitude greater than phytoplankton uptake rates, and heterotrophic bacteria were responsible for generally greater than 50% of total picoplankton P uptake. We hypothesized that this variation in uptake rates reflects variation in cellular P allocation strategies, and found that, indeed, the fraction of cellular P uptake utilized for phospholipid production was significantly higher in heterotrophic bacteria compared with cyanobacterial phytoplankton. These findings indicate that heterotrophic bacteria have a uniquely P-oriented physiology and play a dominant role in cycling dissolved P. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Importance of plant species and external silicon concentration to active silicon uptake and transport.

PubMed

Liang, Yongchao; Hua, Haixia; Zhu, Yong-Guan; Zhang, Jie; Cheng, Chunmei; Römheld, Volker

2006-01-01

Here, we characterized silicon (Si) uptake and xylem loading in Oryza sativa, Zea mays, Helianthus annuus and Benincase hispida in a series of hydroponic experiments. Both active and passive Si-uptake components co-exist in all the plants tested. The active component is the major mechanism responsible for Si uptake in O. sativa and Z. mays. By contrast, passive uptake prevails in H. annuus and B. hispida at a higher external Si concentration (0.85 mM), while the active component constantly exists and contributes to the total Si uptake, especially at a lower external Si concentration (0.085 mM). Short experiments showed that Si uptake was significantly suppressed in O. sativa and Z. mays by metabolic inhibitors or low temperature, regardless of external Si concentrations. By contrast, Si uptake in H. annuus and B. hispida was inhibited more significantly by metabolic inhibitors or low temperature at lower (for example, 0.085 mM) than at higher (for example, 1.70 mM) external Si concentrations. It can be concluded that both active and passive Si-uptake components co-exist in O. sativa, Z. mays, H. annuus and B. hispida, with their relative contribution being dependent much upon both plant species and external Si concentrations.

The effects of intensity on V̇O2 kinetics during incremental free swimming.

PubMed

de Jesus, Kelly; Sousa, Ana; de Jesus, Karla; Ribeiro, João; Machado, Leandro; Rodríguez, Ferran; Keskinen, Kari; Vilas-Boas, João Paulo; Fernandes, Ricardo J

2015-09-01

Swimming and training are carried out with wide variability in distances and intensities. However, oxygen uptake kinetics for the intensities seen in swimming has not been reported. The purpose of this study was to assess and compare the oxygen uptake kinetics throughout low-moderate to severe intensities during incremental swimming exercise. We hypothesized that the oxygen uptake kinetic parameters would be affected by swimming intensity. Twenty male trained swimmers completed an incremental protocol of seven 200-m crawl swims to exhaustion (0.05 m·s(-1) increments and 30-s intervals). Oxygen uptake was continuously measured by a portable gas analyzer connected to a respiratory snorkel and valve system. Oxygen uptake kinetics was assessed using a double exponential regression model that yielded both fast and slow components of the response of oxygen uptake to exercise. From low-moderate to severe swimming intensities changes occurred for the first and second oxygen uptake amplitudes (P ≤ 0.04), time constants (P = 0.01), and time delays (P ≤ 0.02). At the heavy and severe intensities, a notable oxygen uptake slow component (>255 mL·min(-1)) occurred in all swimmers. Oxygen uptake kinetics whilst swimming at different intensities offers relevant information regarding cardiorespiratory and metabolic stress that might be useful for appropriate performance diagnosis and training prescription.

Modification of meta-iodobenzylguanidine uptake in neuroblastoma cells by elevated temperature.

PubMed Central

Armour, A.; Mairs, R. J.; Gaze, M. N.; Wheldon, T. E.

1994-01-01

Successful imaging or treatment of neuroblastoma with 131I-meta-iodobenzylguanidine (131I-mIBG) depends on the selectivity of active (type 1) uptake of mIBG in neuroblastoma cells relative to passive (type 2) uptake present in most normal tissues. This study investigates the effects of moderately elevated temperature (39-41 degrees C) on the cellular uptake of 131I-mIBG in two neuroblastoma cell lines [SK-N-BE(2c) and IMR-32] and in a non-neuronal (ovarian carcinoma) cell line (A2780). In SK-N-BE(2c), a cell line with high active uptake capacity, the specific (type 1) uptake was reduced by 75% (P < 0.001) at 39 degrees C. Both IMR-32 and A2780 have a low capacity for accumulation of mIBG by active uptake. These cell lines demonstrated a statistically significant increase in accumulation at 39 degrees C, mainly as a result of increased non-specific transport. At 41 degrees C uptake of 131I-mIBG was reduced in all cell lines. Thus, the active component of mIBG uptake is more vulnerable to increased temperature than the passive component. It seems probable that moderately increased temperature will have an unfavourable effect on the therapeutic differential for targeted radiotherapy of neuroblastoma using radiolabelled mIBG. PMID:8080728

Contrasting effects of exercise and NOS inhibition on tissue-specific fatty acid and glucose uptake in mice.

PubMed

Rottman, Jeffrey N; Bracy, Deanna; Malabanan, Carlo; Yue, Zou; Clanton, Jeff; Wasserman, David H

2002-07-01

Isotopic techniques were used to test the hypothesis that exercise and nitric oxide synthase (NOS) inhibition have distinct effects on tissue-specific fatty acid and glucose uptakes in a conscious, chronically catheterized mouse model. Uptakes were measured using the radioactive tracers (125)I-labeled beta-methyl-p-iodophenylpentadecanoic acid (BMIPP) and deoxy-[2-(3)H]glucose (DG) during treadmill exercise with and without inhibition of NOS. [(125)I]BMIPP uptake at rest differed substantially among tissues with the highest levels in heart. With exercise, [(125)I]BMIPP uptake increased in both heart and skeletal muscles. In sedentary mice, NOS inhibition induced by nitro-L-arginine methyl ester (L-NAME) feeding increased heart and soleus [(125)I]BMIPP uptake. In contrast, exercise, but not L-NAME feeding, resulted in increased heart and skeletal muscle [2-(3)H]DG uptake. Significant interactions were not observed in the effects of combined exercise and L-NAME feeding on [(125)I]BMIPP and [2-(3)H]DG uptakes. In the conscious mouse, exercise and NOS inhibition produce distinct patterns of tissue-specific fatty acid and glucose uptake; NOS is not required for important components of exercise-associated metabolic signaling, or other mechanisms compensate for the absence of this regulatory mechanism.

Histologic analysis of rabbit liver cancer treated by bulk ultrasound ablation

NASA Astrophysics Data System (ADS)

Karunakaran, Chandra Priya; Rudich, Steven M.; Alqadah, Amel; Burgess, Mark T.; Narmoneva, Daria A.; Mast, T. Douglas

2012-10-01

VX2 rabbit liver cancer, treated in vivo using bulk ultrasound ablation by miniaturized image-ablate arrays, was histologically analyzed using TTC vital stain and DAPI nucleic acid stain. VX2 cells were implanted into rabbit liver lobes and allowed to grow for 11-21 days. Liver lobes containing solid VX2 tumors were then treated with 4.8 MHz, 22.5-38.5 W/cm2 in situ intensity, unfocused ultrasound for exposure times of 20-120 s. After animal sacrifice, thermal lesions were bisected along the imaging/treatment plane, one face stained with TTC, and the other with DAPI. Levels of TTC uptake (no uptake, partial uptake, and complete uptake) in liver parenchyma corresponded to three discrete regions of tan, pink and red color. By processing images of DAPI-stained parenchymal tissue from these three regions, cellular damage was quantified. A viability index parameter incorporating the size and shape of DAPI-stained nuclei correlated significantly with levels of TTC uptake, and thus with local tissue viability. For ablation of normal liver, viability indices for parenchymal regions of no TTC uptake and partial TTC uptake were significantly different from those for viable tissue. For ablation of VX2 tumor, differences in viability index between regions of no TTC uptake and complete TTC uptake were smaller, but significant overall.

Calcium-ion transport by intact Ehrlich ascites-tumour cells. Role of respiratory substrates, Pi and temperature.

PubMed

Charlton, R R; Wenner, C E

1978-03-15

1. The interaction of intact Ehrlich ascites-tumour cells with Ca2+ at 37 degrees C consists of Ca2+ uptake followed by efflux from the cells. Under optimum conditions, two or three cycles of uptake and efflux are observed in the first 15 min after Ca2+ addition. 2. The respiratory substrates malate, succinate and ascorbate plus p-phenylenediamine support Ca2+ uptake. Ca2+ uptake at 37 degrees C is sensitive to the respiratory inhibitors rotenone and antimycin A when appropriate substrates are present. Ca2+ uptake and retention are inhibited by the uncoupler S-13. 3. Increasing extracellular Pi (12 to 30 mM) stimulates uncoupler-sensitive Ca2+ uptake, which reaches a maximum extent of 15 nmol/mg of protein when supported by succinate respiration. Ca2+ efflux is partially inhibited at 30 mM-Pi. 4. Optimum Ca2+ uptake occurs in the presence of succinate and Pi, suggesting that availability of substrate and Pi are rate-limiting. K. Ca2+ uptake occurs at 4 degrees C and is sensitive to uncouplers and oligomycin. Ca2+ efflux at this temperature is minimal. These data are consistent with a model in which passive diffusion of Ca2+ through the plasma membrane is followed by active uptake by the mitochondria. Ca2+ uptake is supported by substrates entering respiration at all three energy-coupling sites. Ca2+ efflux appears to be an active process with a high temperature coefficient.

Comparison of L-serine uptake by human placental microvillous membrane vesicles and placental villous fragments.

PubMed

Brand, A P; Greenwood, S L; Glazier, J D; Bennett, E J; Godfrey, K M; Sibley, C P; Hanson, M A; Lewis, R M

2010-05-01

Both syncytiotrophoblast microvillous plasma membrane vesicles (MVM) and placental villous fragments are used to characterize the placental uptake of maternal substrate and to investigate changes in uptake associated with pathological conditions. However, the two techniques have not been directly compared. In this study uptake of (14)C-L-serine was compared in placental villous fragments and in MVM prepared from the same placentas. (14)C-L-serine uptake into MVM vesicles was mediated by System L and System A and smaller unidentified Na(+)-dependent and Na(+)-independent components. In villous fragments an unidentified Na(+)-dependent component mediated the majority of (14)C-L-serine uptake followed by System A and System L. The unidentified Na(+)-independent component of L-serine uptake was not detected in villous fragments. The ratio of System A activity to System L activity was similar in villous fragments and MVM vesicles. However, the unidentified Na(+)-dependent component in villous fragments was significantly higher than that in MVM vesicles. This indicates that the main differences in serine uptake mechanisms identified using the two techniques were not due to differences in System A and System L activity but to differences in the unidentified Na(+)-dependent component. This study suggests that uptake of L-serine into MVM vesicles and villous fragments via Systems A and L is comparable, but that this is not true for all components of L-serine uptake. (c) 2010 Elsevier Ltd. All rights reserved.

The interrelation between aPKC and glucose uptake in the skeletal muscle during contraction and insulin stimulation.

PubMed

Santos, J M; Benite-Ribeiro, S A; Queiroz, G; Duarte, J A

2014-12-01

Contraction and insulin increase glucose uptake in skeletal muscle. While the insulin pathway, better characterized, requires activation of phosphoinositide 3-kinase (PI3K) and atypical protein kinase (aPKC), muscle contraction seems to share insulin-activated components to increase glucose uptake. This study aimed to investigate the interrelation between the pathway involved in glucose uptake evoked by insulin and muscle contraction. Isolated muscle of rats was treated with solvent (control), insulin, wortmannin (PI3K inhibitor) and the combination of insulin plus wortmannin. After treatment, muscles were electrically stimulated (contracted) or remained at rest. Glucose transporter 4 (GLUT4) localization, glucose uptake and phospho-aPKC (aPKC activated form) were assessed. Muscle contraction and insulin increased glucose uptake in all conditions when compared with controls not stimulating an effect that was accompanied by an increase in GLUT4 and of phospho-aPKC at the muscle membrane. Contracted muscles treated with insulin did not show additive effects on glucose uptake or aPKC activity compared with the response when these stimuli were applied alone. Inhibition of PI3K blocked insulin effect on glucose uptake and aPKC but not in the contractile response. Thus, muscle contraction seems to stimulate aPKC and glucose uptake independently of PI3K. Therefore, aPKC may be a convergence point and a rate limit step in the pathway by which, insulin and contraction, increase glucose uptake in skeletal muscle. Copyright © 2014 John Wiley & Sons, Ltd.

Sorption-reduction coupled gold recovery process boosted by Pycnoporus sanguineus biomass: Uptake pattern and performance enhancement via biomass surface modification.

PubMed

Shi, Chaohong; Zhu, Nengwu; Kang, Naixin; Wu, Pingxiao; Zhang, Xiaoping; Zhang, Yanhong

2017-09-01

Biorecovery is emerging as a promising process to retrieve gold from secondary resources. The present study aimed to explore the uptake pattern of Pycnoporus sanguineus biomass for gold, identify the effective functional groups in gold recovery process, and thus further intensify the process via microbial surface modification. Results showed that P. sanguineus biomass could effectively recover gold with the formation of highly crystal AuNPs without any exogeneous electron donor. Under the conditions of various initial gold concentrations (1.0, 2.0, and 3.0 mM), biomass dosage of 2.0 g/L, solution pH value of 4.0, and incubation temperature of 30°C, the uptake equilibrium established after 4, 8, and 12 h, respectively. The uptake process could be well described by pseudo-second order kinetics model (R 2  = 0.9988) and Langmuir isotherm model (R 2  = 0.9958). The maximum uptake capacity of P. sanguineus reached as high as 358.69 mg/g. Further analysis indicated that amino, carboxyl and hydroxyl groups positively contributed to the uptake process. Among them, amino group significantly favored the uptake of gold during recovery process. When P. sanguineus biomass was modified by introduction of amino group, the gold uptake process was successfully intensified by shortening the uptake period and enhancing the uptake capacity. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1314-1322, 2017. © 2017 American Institute of Chemical Engineers.

Compensatory Root Water Uptake of Overlapping Root Systems

NASA Astrophysics Data System (ADS)

Agee, E.; Ivanov, V. Y.; He, L.; Bisht, G.; Shahbaz, P.; Fatichi, S.; Gough, C. M.; Couvreur, V.; Matheny, A. M.; Bohrer, G.

2015-12-01

Land-surface models use simplified representations of root water uptake based on biomass distributions and empirical functions that constrain water uptake during unfavorable soil moisture conditions. These models fail to capture the observed hydraulic plasticity that allows plants to regulate root hydraulic conductivity and zones of active uptake based on local gradients. Recent developments in root water uptake modeling have sought to increase its mechanistic representation by bridging the gap between physically based microscopic models and computationally feasible macroscopic approaches. It remains to be demonstrated whether bulk parameterization of microscale characteristics (e.g., root system morphology and root conductivity) can improve process representation at the ecosystem scale. We employ the Couvreur method of microscopic uptake to yield macroscopic representation in a coupled soil-root model. Using a modified version of the PFLOTRAN model, which represents the 3-D physics of variably saturated soil, we model a one-hectare temperate forest stand under natural and synthetic climatic forcing. Our results show that as shallow soil layers dry, uptake at the tree and stand level shift to deeper soil layers, allowing the transpiration stream demanded by the atmosphere. We assess the potential capacity of the model to capture compensatory root water uptake. Further, the hydraulic plasticity of the root system is demonstrated by the quick response of uptake to rainfall pulses. These initial results indicate a promising direction for land surface models in which significant three-dimensional information from large root systems can be feasibly integrated into the forest scale simulations of root water uptake.

Effect of cysteine and humic acids on bioavailability of Ag from Ag nanoparticles to a freshwater snail

USGS Publications Warehouse

Luoma, Samuel N.; Tasha Stoiber,; Croteau, Marie-Noele; Isabelle Romer,; Ruth Merrifeild,; Lead, Jamie

2016-01-01

Metal-based engineered nanoparticles (NPs) will undergo transformations that will affect their bioavailability, toxicity and ecological risk when released to the environment, including interactions with dissolved organic material. The purpose of this paper is to determine how interactions with two different types of organic material affect the bioavailability of silver nanoparticles (AgNPs). Silver uptake rates by the pond snail Lymnaea stagnalis were determined after exposure to 25 nmol l-1 of Ag as PVP AgNPs, PEG AgNPs or AgNO3, in the presence of either Suwannee River humic acid or cysteine, a high-affinity thiol-rich organic ligand. Total uptake rate of Ag from the two NPs was either increased or not strongly affected in the presence of 1 – 10 mg 1-1 humic acid. Humic substances contain relatively few strong ligands for Ag explaining their limited effects on Ag uptake rate. In contrast, Ag uptake rate was substantially reduced by cysteine. Three components of uptake from the AgNPs were quantified in the presence of cysteine using a biodynamic modeling approach: uptake of dissolved Ag released by the AgNPs, uptake of a polymer or large (>3kD) Ag-cysteine complex and uptake of the nanoparticle itself. Addition of 1:1 Ag:cysteine reduced concentrations of dissolved Ag, which contributed to, but did not fully explain the reductions in uptake. A bioavailable Ag-cysteine complex (> 3kD) appeared to be the dominant avenue of uptake from both PVP AgNPs and PEG AgNPs in the presence of cysteine. Quantifying the different avenues of uptake sets the stage for studies to assess toxicity unique to NPs.

Radiation increases the cellular uptake of exosomes through CD29/CD81 complex formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazawa, Masaharu; Tomiyama, Kenichi; Saotome-Nakamura, Ai

Highlights: • Radiation increases cellular uptake of exosomes. • Radiation induces colocalization of CD29 and CD81. • Exosomes selectively bind the CD29/CD81 complex. • Radiation increases the cellular uptake of exosomes through CD29/CD81 complex formation. - Abstract: Exosomes mediate intercellular communication, and mesenchymal stem cells (MSC) or their secreted exosomes affect a number of pathophysiologic states. Clinical applications of MSC and exosomes are increasingly anticipated. Radiation therapy is the main therapeutic tool for a number of various conditions. The cellular uptake mechanisms of exosomes and the effects of radiation on exosome–cell interactions are crucial, but they are not well understood.more » Here we examined the basic mechanisms and effects of radiation on exosome uptake processes in MSC. Radiation increased the cellular uptake of exosomes. Radiation markedly enhanced the initial cellular attachment to exosomes and induced the colocalization of integrin CD29 and tetraspanin CD81 on the cell surface without affecting their expression levels. Exosomes dominantly bound to the CD29/CD81 complex. Knockdown of CD29 completely inhibited the radiation-induced uptake, and additional or single knockdown of CD81 inhibited basal uptake as well as the increase in radiation-induced uptake. We also examined possible exosome uptake processes affected by radiation. Radiation-induced changes did not involve dynamin2, reactive oxygen species, or their evoked p38 mitogen-activated protein kinase-dependent endocytic or pinocytic pathways. Radiation increased the cellular uptake of exosomes through CD29/CD81 complex formation. These findings provide essential basic insights for potential therapeutic applications of exosomes or MSC in combination with radiation.« less

The frequency and spectrum of thymus 2-[fluorine-18] fluoro-2-deoxy-D-glucose uptake patterns in hyperthyroidism patients.

PubMed

Chen, Yen-Kung; Yeh, Chia-Lu; Chen, Yen-Ling; Wang, Su-Chen; Cheng, Ru-Hwa; Kao, Pan-Fu

2011-10-01

Thymic hyperplasia is associated with hyperthyroidism. Increased thymus 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) uptake in hyperthyroidism patients has been reported. The aim of this study was to analyze the FDG positron emission tomography (PET) thymus uptake spectrum in patients with active hyperthyroidism with correlation with serum hormones. The prospective study included FDG PET scans from 65 hyperthyroidism patients and 30 subjects with euthyroid status as control group. The intensity of FDG uptake in thyroid and thymus regions was graded subjectively on a five-point scale and semi-quantitatively by measuring standard uptake value (SUV). Correlation coefficient between thymus SUV and serum thyroxine, triiodothyronine, thyrotropin, thyroid peroxidase antibodies (TPO Ab), thyrotropin receptor autoantibody (TR Ab), and thymulin were analyzed. Among 65 hyperthyroidism patients, 30 (46.2%) and 39 (60%) patients showed thyroid and thymus FDG uptake, respectively. The frequency of thymus uptake FDG was high in patients younger than age 40 (28/31, 90.3%). The patterns of the thymic FDG uptake include inverted V or triangular, separated triangular, united nontriangular, unilateral right or left extension, and focal midline. Focal midline FDG uptake was the most common pattern (15/39, 38.5%). None of the control group showed thymus FDG uptake. The correlation coefficient between the FDG uptake SUV levels in thymus and serum hormones, thyrotropin, TPO Ab, TR Ab, and thymulin levels were all low (P > .05). In FDG PET scan, thymus activity was common in hyperthyroidism patients; this should not be misdiagnosed as a malignancy in patients exhibiting weight loss. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

Increased uptake of [123I]-meta-iodobenzylguanidine and [18F]-dopamine in mouse pheochromocytoma cells and tumors after treatment with the histone deacetylase inhibitors romidepsin and trichostatin A

PubMed Central

Martiniova, Lucia; Perera, Shiromi M.; Brouwers, Frederieke M.; Alesci, Salvatore; Abu-Asab, Mones; Marvelle, Amanda F.; Kiesewetter, Dale O.; Thomasson, David; Morris, John C.; Kvetnansky, Richard; Tischler, Arthur S.; Reynolds, James C; Fojo, A. Tito; Pacak, Karel

2014-01-01

Purpose [131I]-meta-iodobenzylguanidine ([131I]-MIBG) is the most commonly employed treatment for metastatic pheochromocytoma and paraganglioma; however, its success is limited. Its efficacy depends on the [131I]-MIBG concentration reached within the tumor through its uptake via the norepinephrine transporter and retention in neurosecretory granules. Purpose is to enhance [123I]-MIBG uptake in cells and liver pheochromocytoma tumors. Experimental Design We report the in vitro effects of two histone deacetylase (HDAC) inhibitors, romidepsin and trichostatin A, on increased uptake of [3H]-norepinephrine and [123I]-MIBG in mouse pheochromocytoma (MPC) cells, and the effect of romidepsin on [18F]-fluorodopamine and [123I]-MIBG uptake in a mouse model of metastatic pheochromocytoma. The effects of both inhibitors on norepinephrine transporter activity were assessed in MPC cells by [123I]-MIBG uptake studies with and without the transporter blocking agent desipramine and the vesicular blocking agent reserpine. Results Both HDAC inhibitors increased [3H]-norepinephrine, [123I]-MIBG, and [18F]-fluorodopamine uptake through the norepinephrine transporter in MPC cells. In vivo, inhibitor treatment resulted in increased uptake of [18F]-fluorodopamine and in pheochromocytoma liver metastases as measured by maximal standardized uptake values on PET imaging (p < 0.001). Analysis of biodistribution after inhibitor treatment confirmed the PET results in that uptake of [123I]-MIBG was significantly increased in liver metastases (p < 0.05). Therefore, HDAC inhibitor treatment increased radioisotope uptake in MPC cells in vitro and in liver metastases in vivo, through increased norepinephrine transporter activity. Conclusion These results suggest that HDAC inhibitors could enhance the therapeutic efficacy of [131I]-MIBG treatment in patients with malignant pheochromocytoma. PMID:21098082

NH4+ transport system of a psychrophilic marine bacterium, Vibrio sp. strain ABE-1.

PubMed

Chou, M; Matsunaga, T; Takada, Y; Fukunaga, N

1999-05-01

NH4(+) transport system of a psychrophilic marine bacterium Vibrio sp. strain ABE-1 (Vibrio ABE-1) was examined by measuring the uptake of [14C]methylammonium ion (14CH3NH3+) into the intact cells. 14CH3NH3+ uptake was detected in cells grown in medium containing glutamate as the sole nitrogen source, but not in those grown in medium containing NH4Cl instead of glutamate. Vibrio ABE-1 did not utilize CH3NH3+ as a carbon or nitrogen source. NH4Cl and nonradiolabeled CH3NH3+ completely inhibited 14CH3NH3+ uptake. These results indicate that 14CH3NH3+ uptake in this bacterium is mediated via an NH4+ transport system and not by a specific carrier for CH3NH3+. The respiratory substrate succinate was required to drive 14CH3NH3+ uptake and the uptake was completely inhibited by KCN, indicating that the uptake was energy dependent. The electrochemical potentials of H+ and/or Na+ across membranes were suggested to be the driving forces for the transport system because the ionophores carbonylcyanide m-chlorophenylhydrazone and monensin strongly inhibited uptake activities at pH 6.5 and 8.5, respectively. Furthermore, KCl activated 14CH3NH3+ uptake. The 14CH3NH3+ uptake activity of Vibrio ABE-1 was markedly high at temperatures between 0 degrees and 15 degrees C, and the apparent Km value for CH3NH3+ of the uptake did not change significantly over the temperature range from 0 degrees to 25 degrees C. Thus, the NH4+ transport system of this bacterium was highly active at low temperatures.

Carotenoids, but not vitamin A, improve iron uptake and ferritin synthesis by Caco-2 cells from ferrous fumarate and NaFe-EDTA.

PubMed

García-Casal, María N; Leets, Irene

2014-04-01

Due to the high prevalence of iron and vitamin A deficiencies and to the controversy about the role of vitamin A and carotenoids in iron absorption, the objectives of this study were to evaluate the following: (1) the effect of a molar excess of vitamin A as well as the role of tannic acid on iron uptake by Caco-2 cells; (2) iron uptake and ferritin synthesis in presence of carotenoids without pro-vitamin A activity: lycopene, lutein, and zeaxantin; and (3) iron uptake and ferritin synthesis from ferrous fumarate and NaFe-EDTA. Cells were incubated 1 h at 37 °C in PBS pH 5.5, containing (59) Fe and different iron compounds. Vitamin A, ferrous fumarate, β-carotene, lycopene, lutein, zeaxantin, and tannic acid were added to evaluate uptake. Ferritin synthesis was measured 24 h after uptake experiments. Vitamin A had no effect on iron uptake by Caco-2 cells, and was significantly lower from NaFe-EDTA than from ferrous fumarate (15.2 ± 2.5 compared with 52.5 ± 8.3 pmol Fe/mg cell protein, respectively). Carotenoids increase uptake up to 50% from fumarate and up to 300% from NaFe-EDTA, since absorption from this compound is low when administered alone. We conclude the following: (1) There was no effect of vitamin A on iron uptake and ferritin synthesis by Caco-2cells. (2) Carotenoids significantly increased iron uptake from ferrous fumarate and NaFe-EDTA, and were capable of partially overcoming the inhibition produced by tannic acid. (3) Iron uptake by Caco-2 cell from NaFe-EDTA was significantly lower compared to other iron compounds, although carotenoids increased and tannic acid inhibited iron uptake comparably to ferrous fumarate. © 2014 Institute of Food Technologists®

Role of Root Hairs and Lateral Roots in Silicon Uptake by Rice

PubMed Central

Ma, Jian Feng; Goto, Shoko; Tamai, Kazunori; Ichii, Masahiko

2001-01-01

The rice plant (Oryza sativa L. cv Oochikara) is known to be a Si accumulator, but the mechanism responsible for the high uptake of Si by the roots is not well understood. We investigated the role of root hairs and lateral roots in the Si uptake using two mutants of rice, one defective in the formation of root hairs (RH2) and another in that of lateral roots (RM109). Uptake experiments with nutrient solution during both a short term (up to 12 h) and relatively long term (26 d) showed that there was no significant difference in Si uptake between RH2 and the wild type (WT), whereas the Si uptake of RM109 was much less than that of WT. The number of silica bodies formed on the third leaf in RH2 was similar to that in WT, but the number of silica bodies in RM109 was only 40% of that in WT, when grown in soil amended with Si under flooded conditions. There was also no difference in the shoot Si concentration between WT and RH2 when grown in soil under upland conditions. Using a multi-compartment transport box, the Si uptake at the root tip (0–1 cm, without lateral roots and root hairs) was found to be similar in WT, RH2, and RM109. However, the Si uptake in the mature zone (1–4 cm from root tip) was significantly lower in RM109 than in WT, whereas no difference was found in Si uptake between WT and RH2. All these results clearly indicate that lateral roots contribute to the Si uptake in rice plant, whereas root hairs do not. Analysis of F2 populations between RM109 and WT showed that Si uptake was correlated with the presence of lateral roots and that the gene controlling formation of lateral roots and Si uptake is a dominant gene. PMID:11743120

Herbivores, tidal elevation, and species richness simultaneously mediate nitrate uptake by seaweed assemblages.

PubMed

Bracken, Matthew E S; Jones, Emily; Williams, Susan L

2011-05-01

In order for research into the consequences of biodiversity changes to be more applicable to real-world ecosystems, experiments must be conducted in the field, where a variety of factors other than diversity can affect the rates of key biogeochemical and physiological processes. Here, we experimentally evaluate the effects of two factors known to affect the diversity and composition of intertidal seaweed assemblages--tidal elevation and herbivory--on nitrate uptake by those assemblages. Based on surveys of community composition at the end of a 1.5-year press experiment, we found that both tide height and herbivores affected seaweed community structure. Not surprisingly, seaweed species richness was greater at lower tidal elevations. Herbivores did not affect richness, but they altered the types of species that were present; seaweed species characterized by higher rates of nitrate uptake were more abundant in herbivore-removal plots. Both tide height and herbivores affected nitrate uptake by seaweed assemblages. Individual seaweed species, as well as entire seaweed assemblages, living higher on the shore had greater rates of biomass-specific nitrate uptake, particularly at high ambient nitrate concentrations. Grazed seaweed assemblages exhibited reduced nitrate uptake, but only at low nitrate concentrations. We evaluated the effect of seaweed richness on nitrate uptake, both alone and after accounting for effects of tidal elevation and herbivores. When only richness was considered, we found no effect on uptake. However, when simultaneous effects of richness, tide height, and herbivores on uptake were evaluated, we found that all three had relatively large and comparable effects on nitrate uptake coefficients and that there was a negative relationship between seaweed richness and nitrate uptake. Particularly because effects of richness on uptake were not apparent unless the effects of tide height and herbivory were also considered, these results highlight the importance of considering the effects of environmental context when evaluating the consequences of biodiversity change in more realistic systems.

Functional imaging in differentiating bronchial masses: an initial experience with a combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan.

PubMed

Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh

2009-10-01

To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.

Uptake of 4-chloro-2-methylphenoxyacetic acid (MCPA) from the apical membrane of Caco-2 cells by the monocarboxylic acid transporter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, Osamu; Tsukagoshi, Kensuke; Endo, Tetsuya

2008-03-15

The cellular uptake mechanism of 4-chloro-2-methylphenoxyacetic acid (MCPA), a phenoxyacetic acid derivative, was investigated using Caco-2 epithelial cells. The cells were incubated with 50 {mu}M MCPA at pH 6.0 and 37 deg. C, and the uptake of MCPA from the apical membranes was measured. The uptake of MCPA was significantly decreased by incubation at low temperature (4 {sup o}C) and markedly increased by lowering the extracellular pH. Pretreatment with a protonophore, carbonylcyanide-p-(trifluoromethoxy)phenylhydrazone (25 {mu}M), or metabolic inhibitors, 2,4-dinitrophenol (1 mM) and sodium azide (10 mM), significantly decreased the uptake of MCPA by 53%, 45% and 48%, respectively. Coincubation of MCPAmore » with 10 mM L-lactic acid or {alpha}-cyano-4-hydroxycinnamate, which is a substrate or an inhibitor of the monocarboxylic acid transporters (MCTs), significantly decreased the uptake of MCPA by 31% and 20%, respectively, and coincubation with benzoic acid profoundly decreased the uptake by 68%. In contrast, coincubation with succinic acid (a dicarboxylic acid) did not affect the uptake. Kinetic analysis of initial MCPA uptake suggested that MCPA is taken up via a carrier-mediated process [K{sub m} = 1.37 {+-} 0.15 mM, V{sub max} = 115 {+-} 6 nmol (mg protein){sup -1} (3 min){sup -1}]. Lineweaver-Burk plots show that benzoic acid competitively inhibits the uptake of MCPA with a K{sub i} value of 4.68 {+-} 1.76 mM. A trans-stimulation effect on MCPA uptake was found in cells preloaded with benzoic acid. These results suggest that the uptake of MCPA from the apical membrane of Caco-2 cells is mainly mediated by common MCTs along with benzoic acid but also in part by L-lactic acid.« less

Key drivers for market penetration of biosimilars in Europe.

PubMed

Rémuzat, Cécile; Dorey, Julie; Cristeau, Olivier; Ionescu, Dan; Radière, Guerric; Toumi, Mondher

2017-01-01

Background & Objectives : Potential drivers and barriers of biosimilar uptake were mainly analysed through qualitative approaches. The study objective was to conduct a quantitative analysis and identify drivers of biosimilar uptake of all available biosimilars in the European Union (EU). Methods : A three-step process was established to identify key drivers for the uptake of biosimilars in the top 10 EU member states (MS) pharmaceutical markets (Belgium, France, Germany, Greece, Hungary, Italy, Poland, Spain, Sweden, and the UK): (1) literature review to identify incentive policies in place to enhance biosimilars adoption; (2) assessment of biosimilar market dynamics based on database analysis; (3) regression model analysis on price using the following explicative variables: incentive policies; price difference between the biosimilar and the originator product; distribution channel; generic uptake and generic price cut; pharmaceutical expenditure per capita; and market competition. Results : At the study cut-off date, 20 biosimilars were available on the market. Incentive policies applied to biosimilars were found to be heterogeneous across countries, and uptakes of biosimilars were also very heterogeneous between different therapeutic classes and countries. Results from the model demonstrated that incentive policies and the date of first biosimilar market entry were correlated to biosimilar uptake. Pharmaceutical expenditure per capita and the highest generic uptake were inversely correlated with biosimilar uptake. Average generic price discount over originator and the number of biosimilars showed a trend toward statistical significance for correlation with biosimilar uptake, but did not reach the significance threshold. Biosimilar price discount over original biologic price, the number of analogues, and the distribution channel were not correlated with the biosimilar uptake. Conclusions : Understanding drivers of biosimilar uptake becomes a critical issue to inform policy decision-makers. This study showed that incentive policies to enhance uptake remain an important driver of biosimilar penetration, while biosimilar price discounts have no impact. Future research is warranted when the biosimilar market gains maturity.

Key drivers for market penetration of biosimilars in Europe

PubMed Central

Rémuzat, Cécile; Dorey, Julie; Cristeau, Olivier; Ionescu, Dan; Radière, Guerric; Toumi, Mondher

2017-01-01

ABSTRACT Background & Objectives: Potential drivers and barriers of biosimilar uptake were mainly analysed through qualitative approaches. The study objective was to conduct a quantitative analysis and identify drivers of biosimilar uptake of all available biosimilars in the European Union (EU). Methods: A three-step process was established to identify key drivers for the uptake of biosimilars in the top 10 EU member states (MS) pharmaceutical markets (Belgium, France, Germany, Greece, Hungary, Italy, Poland, Spain, Sweden, and the UK): (1) literature review to identify incentive policies in place to enhance biosimilars adoption; (2) assessment of biosimilar market dynamics based on database analysis; (3) regression model analysis on price using the following explicative variables: incentive policies; price difference between the biosimilar and the originator product; distribution channel; generic uptake and generic price cut; pharmaceutical expenditure per capita; and market competition. Results: At the study cut-off date, 20 biosimilars were available on the market. Incentive policies applied to biosimilars were found to be heterogeneous across countries, and uptakes of biosimilars were also very heterogeneous between different therapeutic classes and countries. Results from the model demonstrated that incentive policies and the date of first biosimilar market entry were correlated to biosimilar uptake. Pharmaceutical expenditure per capita and the highest generic uptake were inversely correlated with biosimilar uptake. Average generic price discount over originator and the number of biosimilars showed a trend toward statistical significance for correlation with biosimilar uptake, but did not reach the significance threshold. Biosimilar price discount over original biologic price, the number of analogues, and the distribution channel were not correlated with the biosimilar uptake. Conclusions: Understanding drivers of biosimilar uptake becomes a critical issue to inform policy decision-makers. This study showed that incentive policies to enhance uptake remain an important driver of biosimilar penetration, while biosimilar price discounts have no impact. Future research is warranted when the biosimilar market gains maturity. PMID:28265349

DOE Office of Scientific and Technical Information (OSTI.GOV)

Šefl, Martin, E-mail: martin.sefl@gmail.com; Kyriakou, Ioanna; Emfietzoglou, Dimitris, E-mail: demfietz@cc.uoi.gr

Purpose: To study theoretically the impact on cell survival of the radionuclide uptake rate inside tumor cells for a single administration of a radiopharmaceutical. Methods: The instantaneous-uptake model of O’Donoghue [“The impact of tumor cell proliferation in radioimmunotherapy,” Cancer 73, 974–980 (1994)] for a proliferating cell population irradiated by an exponentially decreasing dose-rate is here extended to allow for the monoexponential uptake of the radiopharmaceutical by the targeted cells. The time derivative of the survival curve is studied in detail deducing an expression for the minimum of the surviving fraction and the biologically effective dose (BED). Results: Surviving fractions aremore » calculated over a parameter range that is clinically relevant and broad enough to establish general trends. Specifically, results are presented for the therapy radionuclides Y-90, I-131, and P-32, assuming uptake half-times 1–24 h, extrapolated initial dose-rates 0.5–1 Gy h{sup −1}, and a biological clearance half-life of seven days. Representative radiobiological parameters for radiosensitive and rapidly proliferating tumor cells are used, with cell doubling time equal to 2 days and α-coefficient equal to 0.3 and 0.5 Gy{sup −1}. It is shown that neglecting the uptake phase of the radiopharmaceutical (i.e., assuming instantaneous-uptake) results in a sizeable over-estimation of cell-kill (i.e., under-estimation of cell survival) even for uptake half-times of only a few hours. The differences between the exponential-uptake model and the instantaneous-uptake model become larger for high peak dose-rates, slow uptakes, and (slightly) for long-lived radionuclides. Moreover, the sensitivity of the survival curve on the uptake model was found to be higher for the tumor cells with the larger α-coefficient. Conclusions: The exponential-uptake rate of the radiopharmaceutical inside targeted cells appears to have a considerable effect on the survival of a proliferating cell population and might need to be considered in radiobiological models of tumor cell-kill in radionuclide therapy.« less

Characterization of iron uptake from transferrin by murine endothelial cells.

PubMed

Hallmann, R; Savigni, D L; Morgan, E H; Baker, E

2000-01-01

Iron is required by the brain for normal function, however, the mechanisms by which it crosses the blood-brain barrier (BBB) are poorly understood. The uptake and efflux of transferrin (Tf) and Fe by murine brain-derived (bEND3) and lymph node-derived (m1END1) endothelial cell lines was compared. The effects of iron chelators, metabolic inhibitors and the cellular activators, lipopolysaccharide (LPS) and tumour necrosis factor-alpha (TNF-alpha), on Tf and Fe uptake were investigated. Cells were incubated with 59Fe-125I-Tf; Fe uptake was shown to increase linearly over time for both cell lines, while Tf uptake reached a plateau within 2 h. Both Tf and Fe uptake were saturable. bEND3 cells were shown to have half as many Tf receptors as m1END1 cells, but the mean cycling times of a Tf molecule were the same. Tf and Fe efflux from the cells were measured over time, revealing that after 2 h only 25% of the Tf but 80% of the Fe remained associated with the cells. Of 7 iron chelators, only deferriprone (L1) markedly decreased Tf uptake. However, Fe uptake was reduced by more than 50% by L1, pyridoxal isonicotinoyl hydrazone (PIH) and desferrithiocin (DFT). The cellular activators TNF-alpha or LPS had little effect on Tf turnover, but they accelerated Fe uptake in both endothelial cell types. Phenylarsenoxide (PhAsO) and N-ethyl maleimide (NEM), inhibitors of Tf endocytosis, reduced both Tf and Fe uptake in both cell lines, while bafilomycin A1, an inhibitor of endosomal acidification, reduced Fe uptake but did not affect Tf uptake. The results suggest that Tf and Fe uptake by both bEND3 and m1END1 is via receptor-mediated endocytosis with release of Fe from Tf within the cell and recycling of apo-Tf. On the basis of Tf- and Fe-metabolism both cell lines are similar and therefore well suited for use in in vitro models for Fe transport across the BBB.

Mg(2+) differentially regulates two modes of mitochondrial Ca(2+) uptake in isolated cardiac mitochondria: implications for mitochondrial Ca(2+) sequestration.

PubMed

Blomeyer, Christoph A; Bazil, Jason N; Stowe, David F; Dash, Ranjan K; Camara, Amadou K S

2016-06-01

The manner in which mitochondria take up and store Ca(2+) remains highly debated. Recent experimental and computational evidence has suggested the presence of at least two modes of Ca(2+) uptake and a complex Ca(2+) sequestration mechanism in mitochondria. But how Mg(2+) regulates these different modes of Ca(2+) uptake as well as mitochondrial Ca(2+) sequestration is not known. In this study, we investigated two different ways by which mitochondria take up and sequester Ca(2+) by using two different protocols. Isolated guinea pig cardiac mitochondria were exposed to varying concentrations of CaCl2 in the presence or absence of MgCl2. In the first protocol, A, CaCl2 was added to the respiration buffer containing isolated mitochondria, whereas in the second protocol, B, mitochondria were added to the respiration buffer with CaCl2 already present. Protocol A resulted first in a fast transitory uptake followed by a slow gradual uptake. In contrast, protocol B only revealed a slow and gradual Ca(2+) uptake, which was approximately 40 % of the slow uptake rate observed in protocol A. These two types of Ca(2+) uptake modes were differentially modulated by extra-matrix Mg(2+). That is, Mg(2+) markedly inhibited the slow mode of Ca(2+) uptake in both protocols in a concentration-dependent manner, but not the fast mode of uptake exhibited in protocol A. Mg(2+) also inhibited Na(+)-dependent Ca(2+) extrusion. The general Ca(2+) binding properties of the mitochondrial Ca(2+) sequestration system were reaffirmed and shown to be independent of the mode of Ca(2+) uptake, i.e. through the fast or slow mode of uptake. In addition, extra-matrix Mg(2+) hindered Ca(2+) sequestration. Our results indicate that mitochondria exhibit different modes of Ca(2+) uptake depending on the nature of exposure to extra-matrix Ca(2+), which are differentially sensitive to Mg(2+). The implications of these findings in cardiomyocytes are discussed.

A geographical and seasonal comparison of nitrogen uptake by phytoplankton in the Southern Ocean

NASA Astrophysics Data System (ADS)

Philibert, R.; Waldron, H.; Clark, D.

2015-03-01

The impact of light and nutrients (such as silicate and iron) availability on nitrogen uptake and primary production vary seasonally and regionally in the Southern Ocean. The seasonal cycle of nitrogen uptake by phytoplankton in the Southern Ocean is not fully resolved over an annual scale due to the lack of winter in situ measurements. In this study, nitrate and ammonium uptake rates were measured using 15N tracers during a winter cruise in July 2012 and a summer cruise in February-March 2013. The winter cruise consisted of two legs: leg 1 extended from Cape Town to the ice margin along the GoodHope line and leg 2 stretched from the ice margin to Marion Island. The summer cruise was mostly focused on the subantarctic zone of the Atlantic sector. In winter, nitrogen uptake rates were measured at 55 and 1% of the surface photosynthetically active radiation (sPAR). The summer uptake rates were measured at four light depths corresponding to 55, 30, 10 and 3% sPAR. The integrated nitrate uptake rates during the winter cruise ranged from 0.17 to 5.20 mmol N m-2 d-1 (average 1.14 mmol N m-2 d-1) while the ammonium uptake rates ranged from 0.60 to 32.86 mmol N m-2 d-1 (average 6.73 mmol N m-2 d-1). During the summer cruise, the mean-integrated nitrate uptake rate was 0.20 mmol N m-2 d-1 with a range between 0.10 and 0.38 mmol N m-2 d-1. The integrated ammonium uptake rate averaged 4.39 mmol N m-2 d-1 and ranged from 1.12 to 9.05 mmol N m-2 d-1. The factors controlling nitrogen uptake in winter and summer were investigated. During the winter cruise, it was found that the different nitrogen uptake regimes were not separated by the fronts of the Antarctic Circumpolar Current (ACC). Light (in terms of day length) and ammonium concentration had the most influence on the nitrogen uptake. In the summer, increases in the mixed layer depth (MLD) resulted in increased nitrogen uptake rates. This suggests that the increases in the MLD could be alleviating nutrient limitations experienced by the phytoplankton at the end of summer.

Ammonium and nitrate uptake by leaves of the seagrass Thalassia testudinum: impact of hydrodynamic regime and epiphyte cover on uptake rates

NASA Astrophysics Data System (ADS)

Cornelisen, Christopher D.; Thomas, Florence I. M.

2004-08-01

Seagrasses rely on the uptake of dissolved inorganic nitrogen (DIN) from both sediment pore water and the water column for metabolic processes. Rates at which their leaves remove nutrients from the water column may be influenced by physiological factors, such as enzyme kinetics, and physical factors, including water flow and the presence of epiphytes on the leaf surface. While there is some evidence of the individual effects of these factors on uptake rates for individual plants, there is little information on the effects of these factors on seagrasses that are situated in their natural environment. In order to isolate the combined effects of water flow and epiphyte cover on uptake rates for Thalassia testudinum leaves while they were situated in a natural canopy we applied 15N-labeled ammonium and 15N-labeled nitrate in a series of field flume experiments. Hydrodynamic parameters related to thickness of diffusive boundary layers, including bottom shear stress and the rate of turbulent energy dissipation, were estimated from velocity profiles collected with an acoustic Doppler velocimeter. Rates of NH 4+ uptake for leaves with and without epiphyte cover were proportional to bottom shear stress and energy dissipation rate, while rates of NO 3- uptake were not. For epiphytes, rates of both NH 4+ and NO 3- uptake were dependent on hydrodynamic parameters. Epiphytes covering the leaf surface reduced rates of NH 4+ uptake for seagrass leaves by an amount proportional to the spatial area covered by the epiphytes (˜90%) and although epiphytes reduced NO 3- uptake rates, the amount was not proportional to the extent of epiphyte cover. Results suggest that the rate at which seagrass leaves removed ammonium was limited by the rate of delivery to the surface of the leaves and was greatly reduced due to blockage of active uptake sites by epiphytes. Conversely, rates of nitrate uptake for the seagrass leaves were limited by the rate at which the leaves could process nitrate rather than the rate of delivery. Our findings quantitatively demonstrate the potential impact of hydrodynamic regime and epiphyte cover on rates of DIN uptake by T. testudinum leaves and how the importance of these factors in affecting uptake rates can vary depending on the form of DIN being assimilated.

Brown adipose tissue: a factor to consider in symmetrical tracer uptake in the neck and upper chest region.

PubMed

Hany, Thomas F; Gharehpapagh, Esmaiel; Kamel, Ehab M; Buck, Alfred; Himms-Hagen, Jean; von Schulthess, Gustav K

2002-10-01

Increased symmetrical fluorine-18 fluorodeoxyglucose (FDG) uptake in the cervical and thoracic spine region is well known and has been attributed to muscular uptake. The purpose of this study was to re-evaluate this FDG uptake pattern by means of co-registered positron emission tomography (PET) and computed tomography (CT) imaging, which allowed exact localisation of this uptake. Between April and November 2001, 638 consecutive patients referred for PET/CT were imaged on an in-line PET/CT system (GEMS). This system combines an advanced GE PET scanner and a multirow-detector computer tomograph (Lightspeed, GEMS). The examination included PET with FDG and one CT acquisition with 80 mA. For CT, the following parameters were used: 140 kV, 80 mA, reconstructed slice thickness 5 mm, scan length 867 mm, AT 22.5 s. CT data were used for attenuation correction as well as image co-registration. Image analysis was performed on an Entegra work-station (ELGEMS). All patients with symmetrical uptake within the neck, thorax and shoulder regions were selected and the exact localisation of uptake determined (muscle, bone, fatty tissue or articulation). In 17 of the 638 patients (2.5%), increased, symmetrical FDG uptake in the shoulder region in a typical pattern was found. If extensive, this pattern included FDG activity comparable to brain activity in the lower cervical spine, the shoulder region and the upper thoracic spine in the costovertebral region. A less extensive pattern only involved intermediate FDG uptake in the lower cervical spine and shoulder region or in the shoulder region alone. In seven female patients (average 32.3 years), the extensive uptake pattern was seen. The average body mass index (BMI) was 19.0 (range 16.8-23.4). In the other ten patients (two male, eight female, average age 37.1 years), the average BMI was 22.7 (18.7-27.7). In all patients, the soft tissue uptake was clearly localised within the fatty tissue of the shoulders as demonstrated by PET/CT co-registration. The uptake in the region of the thoracic spine was localised in the region of the costovertebral joints. Symmetrical FDG uptake in the shoulder, neck and thoracic spine region is probably related to uptake in adipose tissue, especially in underweight patients. Hypothetically, this FDG uptake could represent activated brown adipose tissue during increased sympathetic nerve system (SNS) activity due to cold stress.

Iron and gallium increase iron uptake from transferrin by human melanoma cells: further examination of the ferric ammonium citrate-activated iron uptake process.

PubMed

Richardson, D R

2001-04-30

Previously we showed that preincubation of cells with ferric ammonium citrate (FAC) resulted in a marked increase in Fe uptake from both (59)Fe-transferrin (Tf) and (59)Fe-citrate (D.R. Richardson, E. Baker, J. Biol. Chem. 267 (1992) 13972-13979; D.R. Richardson, P. Ponka, Biochim. Biophys. Acta 1269 (1995) 105-114). This Fe uptake process was independent of the transferrin receptor and appeared to be activated by free radicals generated via the iron-catalysed Haber-Weiss reaction. To further understand this process, the present investigation was performed. In these experiments, cells were preincubated for 3 h at 37 degrees C with FAC or metal ion solutions and then labelled for 3 h at 37 degrees C with (59)Fe-Tf. Exposure of cells to FAC resulted in Fe uptake from (59)Fe-citrate that became saturated at an Fe concentration of 2.5 microM, while FAC-activated Fe uptake from Tf was not saturable up to 25 microM. In addition, the extent of FAC-activated Fe uptake from citrate was far greater than that from Tf. These results suggest a mechanism where FAC-activated Fe uptake from citrate may result from direct interaction with the transporter, while Fe uptake from Tf appears indirect and less efficient. Preincubation of cells with FAC at 4 degrees C instead of 37 degrees C prevented its effect at stimulating (59)Fe uptake from (59)Fe-Tf, suggesting that an active process was involved. Previous studies by others have shown that FAC can increase ferrireductase activity that may enhance (59)Fe uptake from (59)Fe-Tf. However, there was no difference in the ability of FAC-treated cells compared to controls to reduce ferricyanide to ferrocyanide, suggesting no change in oxidoreductase activity. To examine if activation of this Fe uptake mechanism could occur by incubation with a range of metal ions, cells were preincubated with either FAC, ferric chloride, ferrous sulphate, ferrous ammonium sulphate, gallium nitrate, copper chloride, zinc chloride, or cobalt chloride. Stimulation of (59)Fe uptake from Tf was shown (in order of potency) with ferric chloride, ferrous sulphate, ferrous ammonium sulphate, and gallium nitrate. The other metal ions examined decreased (59)Fe uptake from Tf. The fact that redox-active Cu(II) ion did not stimulate Fe uptake while redox-inactive Ga(III) did, suggests a mechanism of transporter activation not solely dependent on free radical generation. Indeed, the activation of Fe uptake appears dependent on the presence of the Fe atom itself or a metal ion with atomic similarities to Fe (e.g. Ga).

Can uptake length in strams be determined by nutrient addition experiments? Results from an interbiome comparison study

Treesearch

P. J Mulholland; J. L. Tanks; J. R. Webster; W. B. Bowden; W. K Dodds; S. V. Gregory; N. B Grimm; J. L. Meriam; J. L. Meyer; B. J. Peterson; H. M. Valett; W. M. Wollheim

2002-01-01

Nutrient uptake length is an important parnmeter tor quantifying nutrient cycling in streams. Although nutrient tracer additions are the preierred method for measuring uptake length under ambient nutrient concentrations, short-term nutrient addition experiments have more irequently been used to estimate uptake length in streams. Theoretical analysis of the relationship...

Uptake of Free Choline by Isolated Perfused Rat Liver

NASA Astrophysics Data System (ADS)

Zeisel, Steven H.; Story, David L.; Wurtman, Richard J.; Brunengraber, Henri

1980-08-01

The uptake of free choline by isolated perfused rat liver was characterized. A saturable uptake mechanism [Ka=0.17± 0.07 mM (SD); Vmax=0.84± 0.16\\ μ mol/min × g dry weight] and a nonsaturable mechanism (through which uptake is proportional to choline concentration in the perfusate) were identified. Most of the choline transported into hepatocytes was converted to betaine, phosphorylcholine, or lecithin. Free choline also accumulated within the intracellular space, suggesting that choline oxidase activity does not always limit choline's uptake by the liver.

Gallium scintigraphic pattern in lung CMV infections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganz, W.I.; Cohen, D.; Mallin, W.

1994-05-01

Due to extensive use of prophylactic therapy for Pneumonitis Carinii Pneumonia (PCP), Cytomegalic Viral (CMV) infection may now be the most common lung infection in AIDS patients. This study was performed to determine Gallium-67 patterns in AIDS patients with CMV. Pathology reports were reviewed in AIDS patients who had a dose of 5 to 10 mCi of Gallium-67 citrate. Analysis of images were obtained 48-72 hours later of the entire body was performed. Gallium-67 scans in 14 AIDS patients with biopsy proven CMV, were evaluated for eye, colon, adrenal, lung and renal uptake. These were compared to 40 AIDS patientsmore » without CMV. These controls had infections including PCP, Mycobacterial infections, and lymphocytic interstitial pneumonitis. 100% of CMV patients had bowel uptake greater than or equal to liver. Similar bowel activity was seen in 50% of AIDS patients without CMV. 71% had intense eye uptake which was seen in only 10% of patients without CMV. 50% of CMV patients had renal uptake compared to 5% of non-CMV cases. Adrenal uptake was suggested in 50%, however, SPECT imaging is needed for confirmation. 85% had low grade lung uptake. The low grade lung had perihilar prominence. The remaining 15% had high grade lung uptake (greater than sternum) due to superimposed PCP infection. Colon uptake is very sensitive indicator for CMV infection. However, observing eye, renal, and or adrenal uptake improved the diagnostic specificity. SPECT imaging is needed to confirm renal or adrenal abnormalities due to intense bowel activity present in 100% of cases. When high grade lung uptake is seen superimposed PCP is suggested.« less

Peptide Transporter 1 is Responsible for Intestinal Uptake of the Dipeptide Glycylsarcosine: Studies in Everted Jejunal Rings from Wild-type and Pept1 Null Mice

PubMed Central

Ma, Katherine; Hu, Yongjun; Smith, David E.

2010-01-01

The purpose of this study was to determine the relative importance of PEPT1 in the uptake of peptides/mimetics from mouse small intestine using glycylsarcosine (GlySar). After isolating jejunal tissue from wild-type and Pept1 null mice, 2-cm intestinal segments were everted and mounted on glass rods for tissue uptake studies. [14C]GlySar (4 μM) was studied as a function of time, temperature, sodium and pH, concentration, and potential inhibitors. Compared to wild-type animals, Pept1 null mice exhibited a 78% reduction of GlySar uptake at pH 6.0, 37°C. GlySar uptake showed pH dependence with peak values between pH 6.0-6.5 in wild-type animals, while no such tendency was observed in Pept1 null mice. GlySar exhibited Michaelis-Menten uptake kinetics and a minor nonsaturable component in wild-type animals. In contrast, GlySar uptake occurred by only a nonsaturable process in Pept1 null mice. GlySar uptake was significantly inhibited by dipeptides, aminocephalosporins, angiotensin-converting enzyme inhibitors, and the antiviral prodrug valacyclovir; these inhibitors had little, if any, effect on the uptake of GlySar in Pept1 null mice. The findings demonstrate that PEPT1 plays a critical role in the uptake of GlySar in jejunum, and suggest that PEPT1 is the major transporter responsible for the intestinal absorption of small peptides. PMID:20862774

Exploring uptake and biodistribution of polystyrene (nano)particles in zebrafish embryos at different developmental stages.

PubMed

van Pomeren, M; Brun, N R; Peijnenburg, W J G M; Vijver, M G

2017-09-01

In ecotoxicology, it is continuously questioned whether (nano)particle exposure results in particle uptake and subsequent biodistribution or if particles adsorb to the epithelial layer only. To contribute to answering this question, we investigated different uptake routes in zebrafish embryos and how they affect particle uptake into organs and within whole organisms. This is addressed by exposing three different life stages of the zebrafish embryo in order to cover the following exposure routes: via chorion and dermal exposure; dermal exposure; oral and dermal exposure. How different nanoparticle sizes affect uptake routes was assessed by using polystyrene particles of 25, 50, 250 and 700nm. In our experimental study, we showed that particle uptake in biota is restricted to oral exposure, whereas the dermal route resulted in adsorption to the epidermis and gills only. Ingestion followed by biodistribution was observed for the tested particles of 25 and 50nm. The particles spread through the body and eventually accumulated in specific organs and tissues such as the eyes. Particles larger than 50nm were predominantly adsorbed onto the intestinal tract and outer epidermis of zebrafish embryos. Embryos exposed to particles via both epidermis and intestine showed highest uptake and eventually accumulated particles in the eye, whereas uptake of particles via the chorion and epidermis resulted in marginal uptake. Organ uptake and internal distribution should be monitored more closely to provide more in depth information of the toxicity of particles. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Response of soil methane uptake to simulated nitrogen deposition and grazing management across three types of steppe in Inner Mongolia, China.

PubMed

Li, Xianglan; He, Hong; Yuan, Wenping; Li, Linghao; Xu, Wenfang; Liu, Wei; Shi, Huiqiu; Hou, Longyu; Chen, Jiquan; Wang, Zhiping

2018-01-15

The response of soil methane (CH 4 ) uptake to increased nitrogen (N) deposition and grazing management was studied in three types of steppe (i.e., meadow steppe, typical steppe, and desert steppe) in Inner Mongolia, China. The experiment was designed with four simulated N deposition rates such as 0, 50, 100, and 200kgNha -1 , respectively, under grazed and fenced management treatments. Results showed that the investigated steppes were significant sinks for CH 4 , with an uptake flux of 1.12-3.36kgha -1 over the grass growing season and that the magnitude of CH 4 uptake significantly (P<0.05) decreased with increasing N deposition rates. The soil CH 4 uptake rates were highest in the desert steppe, moderate in the typical steppe, and lowest in the meadow steppe. Compared with grazed plots, fencing increased the CH 4 uptake by 4.7-40.2% with a mean value of 20.2% across the three different steppe types. The responses of soil CH 4 uptake to N deposition in the continental steppe varied depending on the N deposition rate, steppe type, and grazing management. A significantly positive correlation between CH 4 uptake and soil temperature was found in this study, whereas no significant relationship between soil moisture and CH 4 uptake occurred. Our results may contribute to the improvement of model parameterization for simulating biosphere-atmosphere CH 4 exchange processes and for evaluating the climate change feedback on CH 4 soil uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

A Modified Procedure for Estimating the Impact of the Uptake on the Overall Biliary Clearance in Sandwich Culture of Rat Hepatocytes.

PubMed

Jemnitz, Katalin; Szabo, Monika; Batai-Konczos, Attila; Szabo, Pal; Magda, Balazs; Veres, Zsuzsa

2015-01-01

Sandwich culture of hepatocytes is commonly applied for the prediction of in vivo biliary clearance (CLbil). In this paper, we present a modified procedure for the determination of in vitro CLbil in sandwich culture of rat hepatocytes, which allows the estimation of the impact of uptake processes on the overall CLbil. The main point of this modification is the separation of uptake and efflux processes. Ten drugs from four biopharmaceutics drug disposition classification system classes were chosen in order to demonstrate the advantages of this method: 1) the uptake is performed identically before the canaliculi are opened, thus the efflux starts at the same intracellular concentration of the drugs and the effect of Ca2+/Mg2+ depletion on the uptake is excluded; 2) exact intracellular concentrations can be measured at the start and at the end of the efflux; 3) the biliary clearance can be determined irrespective of the uptake; 4) the canalicular and the sinusoidal transport can be measured simultaneously; 5) drug-drug interactions concerning uptake and efflux transporters can be estimated independently. Depending on the degree of uptake, CLbil,app (calculated using the concentration of drugs in the medium) was significantly higher (sulfasalazine, fluvastatin, rosuvastatin, atorvastatin) or lower (pravastatin, procainamide) than CLbil,int (calculated using the intracellular concentration of drugs). When the uptake had no impact on the CLbil, the apparent and intrinsic CLbil did not differ significantly (lovastatin, rifampicin, quetiapine). Our results confirm that transporters may play a significant role in the uptake of drugs both with high and poor permeability and solubility.

Effects of fat on glucose uptake and utilization in patients with non-insulin-dependent diabetes.

PubMed Central

Boden, G; Chen, X

1995-01-01

It was the aim of this study to determine whether FFA inhibit insulin-stimulated whole body glucose uptake and utilization in patients with non-insulin-dependent diabetes. We performed five types of isoglycemic (approximately 11mM) clamps: (a) with insulin; (b) with insulin plus fat/heparin; (c) with insulin plus glycerol; (d) with saline; (e) with saline plus fat/heparin and two types of euglycemic (approximately 5mM) clamps: (a) with insulin; (b) with insulin plus fat/heparin. During these studies, we determined rates of glucose uptake, glycolysis (both with 3[3H] glucose), glycogen synthesis (determined as glucose uptake minus glycolysis), carbohydrate oxidation (by indirect calorimetry) and nonoxidative glycolysis (determined as glycolysis minus carbohydrate oxidation). Fat/heparin infusion did not affect basal glucose uptake, but inhibited total stimulated (insulin stimulated plus basal) glucose uptake by 40-50% in isoglycemic and in euglycemic patients at plasma FFA concentration of approximately 950 and approximately 550 microM, respectively. In isoglycemic patients, the 40-50% inhibition of total stimulated glucose uptake was due to near complete inhibition of the insulin-stimulated part of glucose uptake. Proportional inhibition of glucose uptake, glycogen synthesis, and glycolysis suggested a major FFA-mediated defect involving glucose transport and/or phosphorylation. In summary, fat produced proportional inhibitions of insulin-stimulated glucose uptake and of intracellular glucose utilization. We conclude, that physiologically elevated levels of FFa could potentially be responsible for a large part of the peripheral insulin resistance in patients with non-insulin-dependent diabetes mellitus. PMID:7657800

Effects of fat on glucose uptake and utilization in patients with non-insulin-dependent diabetes.

PubMed

Boden, G; Chen, X

1995-09-01

It was the aim of this study to determine whether FFA inhibit insulin-stimulated whole body glucose uptake and utilization in patients with non-insulin-dependent diabetes. We performed five types of isoglycemic (approximately 11mM) clamps: (a) with insulin; (b) with insulin plus fat/heparin; (c) with insulin plus glycerol; (d) with saline; (e) with saline plus fat/heparin and two types of euglycemic (approximately 5mM) clamps: (a) with insulin; (b) with insulin plus fat/heparin. During these studies, we determined rates of glucose uptake, glycolysis (both with 3[3H] glucose), glycogen synthesis (determined as glucose uptake minus glycolysis), carbohydrate oxidation (by indirect calorimetry) and nonoxidative glycolysis (determined as glycolysis minus carbohydrate oxidation). Fat/heparin infusion did not affect basal glucose uptake, but inhibited total stimulated (insulin stimulated plus basal) glucose uptake by 40-50% in isoglycemic and in euglycemic patients at plasma FFA concentration of approximately 950 and approximately 550 microM, respectively. In isoglycemic patients, the 40-50% inhibition of total stimulated glucose uptake was due to near complete inhibition of the insulin-stimulated part of glucose uptake. Proportional inhibition of glucose uptake, glycogen synthesis, and glycolysis suggested a major FFA-mediated defect involving glucose transport and/or phosphorylation. In summary, fat produced proportional inhibitions of insulin-stimulated glucose uptake and of intracellular glucose utilization. We conclude, that physiologically elevated levels of FFa could potentially be responsible for a large part of the peripheral insulin resistance in patients with non-insulin-dependent diabetes mellitus.

Baseline Tumor Lipiodol Uptake after Transarterial Chemoembolization for Hepatocellular Carcinoma: Identification of a Threshold Value Predicting Tumor Recurrence.

PubMed

Matsui, Yusuke; Horikawa, Masahiro; Jahangiri Noudeh, Younes; Kaufman, John A; Kolbeck, Kenneth J; Farsad, Khashayar

2017-12-01

The aim of the study was to evaluate the association between baseline Lipiodol uptake in hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE) with early tumor recurrence, and to identify a threshold baseline uptake value predicting tumor response. A single-institution retrospective database of HCC treated with Lipiodol-TACE was reviewed. Forty-six tumors in 30 patients treated with a Lipiodol-chemotherapy emulsion and no additional particle embolization were included. Baseline Lipiodol uptake was measured as the mean Hounsfield units (HU) on a CT within one week after TACE. Washout rate was calculated dividing the difference in HU between the baseline CT and follow-up CT by time (HU/month). Cox proportional hazard models were used to correlate baseline Lipiodol uptake and other variables with tumor response. A receiver operating characteristic (ROC) curve was used to identify the optimal threshold for baseline Lipiodol uptake predicting tumor response. During the follow-up period (mean 5.6 months), 19 (41.3%) tumors recurred (mean time to recurrence = 3.6 months). In a multivariate model, low baseline Lipiodol uptake and higher washout rate were significant predictors of early tumor recurrence ( P = 0.001 and < 0.0001, respectively). On ROC analysis, a threshold Lipiodol uptake of 270.2 HU was significantly associated with tumor response (95% sensitivity, 93% specificity). Baseline Lipiodol uptake and washout rate on follow-up were independent predictors of early tumor recurrence. A threshold value of baseline Lipiodol uptake > 270.2 HU was highly sensitive and specific for tumor response. These findings may prove useful for determining subsequent treatment strategies after Lipiodol TACE.

18F-FDG uptake in the colon is modulated by metformin but not associated with core body temperature and energy expenditure.

PubMed

Bahler, Lonneke; Holleman, Frits; Chan, Man-Wai; Booij, Jan; Hoekstra, Joost B; Verberne, Hein J

2017-01-01

Physiological colonic 18F-fluorodeoxyglucose (18F-FDG) uptake is a frequent finding on 18F-FDG positron emission tomography computed tomography (PET-CT). Interestingly, metformin, a glucose lowering drug associated with moderate weight loss, is also associated with an increased colonic 18F-FDG uptake. Consequently, increased colonic glucose use might partly explain the weight losing effect of metformin when this results in an increased energy expenditure and/or core body temperature. Therefore, we aimed to determine whether metformin modifies the metabolic activity of the colon by increasing glucose uptake. In this open label, non-randomized, prospective mechanistic study, we included eight lean and eight overweight males. We measured colonic 18F-FDG uptake on PET-CT, energy expenditure and core body temperature before and after the use of metformin. The maximal colonic 18F-FDG uptake was measured in 5 separate segments (caecum, colon ascendens,-transversum,-descendens and sigmoid). The maximal colonic 18F-FDG uptake increased significantly in all separate segments after the use of metformin. There was no significant difference in energy expenditure or core body temperature after the use of metformin. There was no correlation between maximal colonic 18F-FDG uptake and energy expenditure or core body temperature. Metformin significantly increases colonic 18F-FDG uptake, but this increased uptake is not associated with an increase in energy expenditure or core body temperature. Although the colon might be an important site of the glucose plasma lowering actions of metformin, this mechanism of action does not explain directly any associated weight loss.

Ceruloplasmin ferroxidase activity stimulates cellular iron uptake by a trivalent cation-specific transport mechanism

NASA Technical Reports Server (NTRS)

Attieh, Z. K.; Mukhopadhyay, C. K.; Seshadri, V.; Tripoulas, N. A.; Fox, P. L.

1999-01-01

The balance required to maintain appropriate cellular and tissue iron levels has led to the evolution of multiple mechanisms to precisely regulate iron uptake from transferrin and low molecular weight iron chelates. A role for ceruloplasmin (Cp) in vertebrate iron metabolism is suggested by its potent ferroxidase activity catalyzing conversion of Fe2+ to Fe3+, by identification of yeast copper oxidases homologous to Cp that facilitate high affinity iron uptake, and by studies of "aceruloplasminemic" patients who have extensive iron deposits in multiple tissues. We have recently shown that Cp increases iron uptake by cultured HepG2 cells. In this report, we investigated the mechanism by which Cp stimulates cellular iron uptake. Cp stimulated the rate of non-transferrin 55Fe uptake by iron-deficient K562 cells by 2-3-fold, using a transferrin receptor-independent pathway. Induction of Cp-stimulated iron uptake by iron deficiency was blocked by actinomycin D and cycloheximide, consistent with a transcriptionally induced or regulated transporter. Cp-stimulated iron uptake was completely blocked by unlabeled Fe3+ and by other trivalent cations including Al3+, Ga3+, and Cr3+, but not by divalent cations. These results indicate that Cp utilizes a trivalent cation-specific transporter. Cp ferroxidase activity was required for iron uptake as shown by the ineffectiveness of two ferroxidase-deficient Cp preparations, copper-deficient Cp and thiomolybdate-treated Cp. We propose a model in which iron reduction and subsequent re-oxidation by Cp are essential for an iron uptake pathway with high ion specificity.

Epidermal Growth Factor Enhances Cellular Uptake of Polystyrene Nanoparticles by Clathrin-Mediated Endocytosis

PubMed Central

Phuc, Le Thi Minh; Taniguchi, Akiyoshi

2017-01-01

The interaction between nanoparticles and cells has been studied extensively, but most research has focused on the effect of various nanoparticle characteristics, such as size, morphology, and surface charge, on the cellular uptake of nanoparticles. In contrast, there have been very few studies to assess the influence of cellular factors, such as growth factor responses, on the cellular uptake efficiency of nanoparticles. The aim of this study was to clarify the effects of epidermal growth factor (EGF) on the uptake efficiency of polystyrene nanoparticles (PS NPs) by A431 cells, a human carcinoma epithelial cell line. The results showed that EGF enhanced the uptake efficiency of A431 cells for PS NPs. In addition, inhibition and localization studies of PS NPs and EGF receptors (EGFRs) indicated that cellular uptake of PS NPs is related to the binding of EGF–EGFR complex and PS NPs. Different pathways are used to enter the cells depending on the presence or absence of EGF. In the presence of EGF, cellular uptake of PS NPs is via clathrin-mediated endocytosis, whereas, in the absence of EGF, uptake of PS NPs does not involve clathrin-mediated endocytosis. Our findings indicate that EGF enhances cellular uptake of PS NPs by clathrin-mediated endocytosis. This result could be important for developing safe nanoparticles and their safe use in medical applications. PMID:28629179

Effect of Changes in Transepithelial Transport on the Uptake of Sodium across the Outer Surface of the Frog Skin

PubMed Central

Biber, Thomas U. L.

1971-01-01

The unidirectional sodium, uptake at the outer surface of the frog skin was measured by the method described by Biber and Curran (8). With bathing solutions containing 6 mM NaCl there is a good correlation between sodium uptake and short-circuit current (SCC) measured simultaneously except that the average uptake is about 40% higher than the average SCC. The discrepancy between uptake and SCC increases approximately in proportion to an increase in sodium concentration of the bathing solutions. Amiloride inhibits the unidirectional sodium uptake by 21 and 69% at a sodium concentration of 115 and 6 mM, respectively. This indicates that amiloride acts on the entry step of sodium but additional effects cannot be excluded. The sodium, uptake is not affected by 10-4 M ouabain at a sodium concentration of 115 mM but is inhibited by 40% at a sodium concentration of 6 mM. Replacement of air by nitrogen leads to a 40% decrease of sodium uptake at a sodium concentration of 6 mM. The results support the view proposed previously (8) that the sodium uptake is made up of two components, a linear component which is, essentially, not involved in transepithelial movement of sodium and a saturating component which reflects changes in transepithelial transport. Amiloride, seems largely to affect the saturating component. PMID:5559619

The contribution of spray formulation component variables to foliar uptake of agrichemicals.

PubMed

Forster, W Alison; Kimberley, Mark O

2015-09-01

The objective of the present study was to determine the contribution of the active ingredient (AI) and surfactant, and their concentrations, to the foliar uptake of agrichemicals, and to examine the physical properties that would need to be included in a model for foliar uptake. All spray formulation component variables significantly affected uptake, explaining 73% of the deviance. The deviance explained by each factor ranged from 43% (AI concentration nested within AI) to 5.6% (surfactant). The only significant interaction was between AI and surfactant, explaining 15.8% of the deviance. Overall, 90% of the deviance could be explained by the variables and their first-order interactions. Uptake increased with increasing lipophilicity of the AI at concentrations below those causing precipitation on the leaf surface. AI concentration had a far greater (negative) effect on the uptake of the lipophilic molecule epoxiconazole. The uptake of 2-deoxy-D-glucose (DOG) and 2,4-dichlorophenoxyacetic acid (2,4-D) increased with increasing hydrophile-lipophile balance (HLB) of the surfactant, the effect of HLB being far greater on the hydrophilic molecule DOG. However, the differences observed in epoxiconazole uptake owing to the surfactant were strongly positively related to the spread area of the formulation on the leaf surface. For all AIs, uptake increased in a similar manner with increasing molar surfactant concentration. © 2014 Society of Chemical Industry.

Methionine Uptake and Required Radiation Dose to Control Glioblastoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iuchi, Toshihiko, E-mail: tiuchi@chiba-cc.jp; Hatano, Kazuo; Uchino, Yoshio

Purpose: The purpose of this study was to retrospectively assess the feasibility of radiation therapy planning for glioblastoma multiforme (GBM) based on the use of methionine (MET) positron emission tomography (PET), and the correlation among MET uptake, radiation dose, and tumor control. Methods and Materials: Twenty-two patients with GBM who underwent MET-PET prior to radiation therapy were enrolled. MET uptake in 30 regions of interest (ROIs) from 22 GBMs, biologically effective doses (BEDs) for the ROIs and their ratios (MET uptake:BED) were compared in terms of whether the ROIs were controlled for >12 months. Results: MET uptake was significantly correlated withmore » tumor control (odds ratio [OR], 10.0; P=.005); however, there was a higher level of correlation between MET uptake:BED ratio and tumor control (OR, 40.0; P<.0001). These data indicated that the required BEDs for controlling the ROIs could be predicted in terms of MET uptake; BED could be calculated as [34.0 × MET uptake] Gy from the optimal threshold of the MET uptake:BED ratio for tumor control. Conclusions: Target delineation based on MET-PET was demonstrated to be feasible for radiation therapy treatment planning. MET-PET could not only provide precise visualization of infiltrating tumor cells but also predict the required radiation doses to control target regions.« less

Epidermal Growth Factor Enhances Cellular Uptake of Polystyrene Nanoparticles by Clathrin-Mediated Endocytosis.

PubMed

Phuc, Le Thi Minh; Taniguchi, Akiyoshi

2017-06-19

The interaction between nanoparticles and cells has been studied extensively, but most research has focused on the effect of various nanoparticle characteristics, such as size, morphology, and surface charge, on the cellular uptake of nanoparticles. In contrast, there have been very few studies to assess the influence of cellular factors, such as growth factor responses, on the cellular uptake efficiency of nanoparticles. The aim of this study was to clarify the effects of epidermal growth factor (EGF) on the uptake efficiency of polystyrene nanoparticles (PS NPs) by A431 cells, a human carcinoma epithelial cell line. The results showed that EGF enhanced the uptake efficiency of A431 cells for PS NPs. In addition, inhibition and localization studies of PS NPs and EGF receptors (EGFRs) indicated that cellular uptake of PS NPs is related to the binding of EGF-EGFR complex and PS NPs. Different pathways are used to enter the cells depending on the presence or absence of EGF. In the presence of EGF, cellular uptake of PS NPs is via clathrin-mediated endocytosis, whereas, in the absence of EGF, uptake of PS NPs does not involve clathrin-mediated endocytosis. Our findings indicate that EGF enhances cellular uptake of PS NPs by clathrin-mediated endocytosis. This result could be important for developing safe nanoparticles and their safe use in medical applications.

Uptake of HNO3 on aviation kerosene and aircraft engine soot: influences of H2O or/and H2SO4.

PubMed

Loukhovitskaya, Ekaterina E; Talukdar, Ranajit K; Ravishankara, A R

2013-06-13

The uptake of HNO3 on aviation kerosene soot (TC-1 soot) was studied in the absence and presence of water vapor at 295 and 243 K. The influence of H2SO4 coating of the TC-1 soot surface on HNO3 uptake was also investigated. Only reversible uptake of HNO3 was observed. HONO and NO2, potential products of reactive uptake of HNO3, were not observed under any conditions studied here. The uptake of nitric acid increased slightly with relative humidity (RH). Coating of the TC-1 soot surface with sulfuric acid decreased the uptake of HNO3 and did not lead to displacement of H2SO4 from the soot surface. A limited set of measurements was carried out on soot generated by aircraft engine combustor (E-soot) with results similar to those on TC-1 soot. The influence of water on HNO3 uptake on E-soot appeared to be more pronounced than on TC-1 soot. Our results suggest that HNO3 loss in the upper troposphere due to soot is not significant except perhaps in aircraft exhaust plumes. Our results also suggest that HNO3 is not converted to either NO2 or HONO upon its uptake on soot in the atmosphere.

Human Papillomavirus Vaccine Uptake in Adolescent Boys: An Evidence Review.

PubMed

Voss, Danielle S; Wofford, Linda G

2016-10-01

Despite evidence-based guidelines recommending routine vaccination against human papillomavirus (HPV) for adolescent boys, ages 11-12 years, vaccine uptake among this population remains low. To examine reasons for low HPV quadrivalent vaccine uptake and methods available to increase vaccine uptake among adolescent males, ages 11-12 years. Of 341 identified studies, 30 were included from three databases. The 30 studies were grouped into six categories: population-specific, problem-specific, educational interventions, theory-specific, political implications, and foundational guidelines and Websites. Among eight studies, low vaccine uptake was attributed to lack of parental, adolescent, and physician knowledge of HPV4 vaccine availability and recommendations. HPV4 vaccine educational interventions for parents and adolescents were the most effective for promoting vaccine uptake. Theory applications and gain-framed messages were shown to be effective for assessing HPV vaccine attitudes and perceptions. Political implication studies reveal the need for political and financial measures to encourage HPV vaccine acceptability among the population. To promote HPV vaccine uptake among adolescent males, providers must remain current with HPV vaccine recommendations and offer parental and adolescent HPV education focusing on benefits of vaccine acceptance and risks of vaccine refusal. The results of this review inform our understanding of effective educational strategies to positively impact HPV vaccine uptake in adolescent males. Based on this review, clinicians can employ several evidence-based educational strategies to facilitate HPV vaccine uptake. © 2016 Sigma Theta Tau International.

Chloride and sodium uptake potential over an entire rotation of Populus irrigated with landfill leachate.

PubMed

Zalesny, Jill A; Zalesny, Ronald S

2009-07-01

There is a need for information about the response of Populus genotypes to repeated application of high-salinity water and nutrient sources throughout an entire rotation. We have combined establishment biomass and uptake data with mid- and full-rotation growth data to project potential chloride (Cl-) and sodium (Na+) uptake for 2- to 11-year-old Populus in the north central United States. Our objectives were to identify potential levels of uptake as the trees developed and stages of plantation development that are conducive to variable application rates of high-salinity irrigation. The projected cumulative uptake of Cl- and Na+ during mid-rotation plantation development was stable 2 to 3 years after planting but increased steadily from year 3 to 6. Year six cumulative uptake ranged from 22 to 175 kg Cl- ha(-1) and 8 to 74 kg Na+ ha(-1), while annual uptake ranged from 8 to 54 kg Cl- ha(-1) yr(-1) and 3 to 23 kg Na+ ha(-1) yr(-1). Full-rotation uptake was greatest from 4 to 9 years (Cl-) and 4 to 8 years (Na+), with maximum levels of Cl- (32 kg ha(-1) yr(-1)) and Na+ (13 kg ha(-1) yr(-1)) occurring in year six. The relative uptake potential of Cl- and Na+ at peak accumulation (year six) was 2.7 times greater than at the end of the rotation.

5'-AMP-activated protein kinase increases glucose uptake independent of GLUT4 translocation in cardiac myocytes.

PubMed

Lee, Christopher T; Ussher, John R; Mohammad, Askar; Lam, Anna; Lopaschuk, Gary D

2014-04-01

Glucose uptake and glycolysis are increased in the heart during ischemia, and this metabolic alteration constitutes an important contributing factor towards ischemic injury. Therefore, it is important to understand glucose uptake regulation in the ischemic heart. There are primarily 2 glucose transporters controlling glucose uptake into cardiac myocytes: GLUT1 and GLUT4. In the non-ischemic heart, insulin stimulates GLUT4 translocation to the sarcolemmal membrane, while both GLUT1 and GLUT4 translocation can occur following AMPK stimulation. Using a newly developed technique involving [(3)H]2-deoxyglucose, we measured glucose uptake in H9c2 ventricular myoblasts, and demonstrated that while insulin has no detectable effect on glucose uptake, phenformin-induced AMPK activation increases glucose uptake 2.5-fold. Furthermore, insulin treatment produced no discernible effect on either Akt serine 473 phosphorylation or AMPKα threonine 172 phosphorylation, while treatment with phenformin results in an increase in AMPKα threonine 172 phosphorylation, and a decrease in Akt serine 473 phosphorylation. Visualization of a dsRed-GLUT4 fusion construct in H9c2 cells by laser confocal microscopy showed that unlike insulin, AMPK activation did not redistribute GLUT4 to the sarcolemmal membrane, suggesting that AMPK may regulate glucose uptake via another glucose transporter. These studies suggest that AMPK is a major regulator of glucose uptake in cardiac myocytes.

NO3 uptake in shallow, oligotrophic, mountain lakes: The influence of elevated NO3 concentrations

USGS Publications Warehouse

Nydick, K.R.; LaFrancois, B.M.; Baron, Jill S.

2004-01-01

Nutrient enrichment experiments were conducted in 1.2-m deep enclosures in 2 shallow, oligotrophic, mountain lakes. 15N-NO3 isotope tracer was used to compare the importance of phytoplankton and benthic compartments (epilithon, surface sediment [epipelon], and subsurface sediment) for NO3 uptake under high and low NO3 conditions. NO3 uptake approached saturation in the high-N lake, but not in the low-N lake. The capacity of phytoplankton and benthic compartments to take up NO3 differed among treatments and between lakes, and depended on water-column nutrient conditions and the history of NO3 availability. Phytoplankton productivity responded strongly to addition of limiting nutrients, and NO3 uptake was related to phytoplankton biomass and photosynthesis. However, more NO3 usually was taken up by benthic compartments (57–92% combined) than by phytoplankton, even though the response of benthic algal biomass to nutrient additions was less pronounced than that of phytoplankton and benthic NO3 uptake was unrelated to benthic algal biomass. In the low-N lake where NO3 uptake was unsaturated, C content or % was related to NO3 uptake in benthic substrates, suggesting that heterotrophic bacterial processes could be important in benthic NO3 uptake. These results suggest that phytoplankton are most sensitive to nutrient additions, but benthic processes are important for NO3 uptake in shallow, oligotrophic lakes.

Oxyntomodulin stimulates intestinal glucose uptake in rats.

PubMed

Collie, N L; Zhu, Z; Jordan, S; Reeve, J R

1997-06-01

Enteroglucagon peptides have long been proposed as mediators of intestinal adaptation, including mucosal growth and nutrient absorptive capacity. The hypothesis that infusions of oxyntomodulin, a bioactive form of enteroglucagon, would stimulate glucose and amino acid uptake was tested and its effects were compared with those of glucagon. Rats were infused intravenously via minipumps with either saline, rat oxyntomodulin (0.47 nmol x kg(-1) x h[-1]), or glucagon (0.88 nmol x kg(-1) x h[-1]) for 7 days, and plasma hormone levels were measured. At death, intestinal dimensions and brush border uptake of D-glucose and L-proline were measured using an in vitro everted sleeve technique. Plasma enteroglucagon and glucagon levels were increased 4- and 12-fold, respectively, but there were no effects on food intake, body weight, or intestinal dimensions. In contrast, oxyntomodulin and glucagon significantly stimulated total intestinal glucose uptake capacity by 44% and 53%, respectively, over controls. Oxyntomodulin most potently enhanced glucose uptake in the ileum (215%), whereas glucagon's greatest effect was in the jejunum (63%-85%). However, neither peptide affected proline uptake. These results support a new, specific action for oxyntomodulin in intestinal adaptation as a glucose uptake stimulator and confirm glucagon's role as a regulator of glucose uptake.

Role of the ocean's AMOC in setting the uptake efficiency of transient tracers

NASA Astrophysics Data System (ADS)

Romanou, A.; Marshall, J.; Kelley, M.; Scott, J. R.

2017-12-01

The central role played by the ocean's Atlantic Meridional Overturning Circulation (AMOC) in the uptake and sequestration of transient tracers is studied in a series of experiments with the Goddard Institute for Space Studies and Massachusetts Institute of Technology ocean circulation models. Forced by observed atmospheric time series of CFC-11, both models exhibit realistic distributions in the ocean, with similar surface biases but different response over time. To better understand what controls uptake, we ran idealized forcing experiments in which the AMOC strength varied over a wide range, bracketing the observations. We found that differences in the strength and vertical scale of the AMOC largely accounted for the different rates of CFC-11 uptake and vertical distribution thereof. A two-box model enables us to quantify and relate uptake efficiency of passive tracers to AMOC strength and how uptake efficiency decreases in time. We also discuss the relationship between passive tracer and heat uptake efficiency, of which the latter controls the transient climate response to anthropogenic forcing in the North Atlantic. We find that heat uptake efficiency is substantially less (by about a factor of 5) than that for a passive tracer.

Dermal uptake of phthalates from clothing: Comparison of model to human participant results.

PubMed

Morrison, G C; Weschler, C J; Bekö, G

2017-05-01

In this research, we extend a model of transdermal uptake of phthalates to include a layer of clothing. When compared with experimental results, this model better estimates dermal uptake of diethylphthalate and di-n-butylphthalate (DnBP) than a previous model. The model predictions are consistent with the observation that previously exposed clothing can increase dermal uptake over that observed in bare-skin participants for the same exposure air concentrations. The model predicts that dermal uptake from clothing of DnBP is a substantial fraction of total uptake from all sources of exposure. For compounds that have high dermal permeability coefficients, dermal uptake is increased for (i) thinner clothing, (ii) a narrower gap between clothing and skin, and (iii) longer time intervals between laundering and wearing. Enhanced dermal uptake is most pronounced for compounds with clothing-air partition coefficients between 10 4 and 10 7 . In the absence of direct measurements of cotton cloth-air partition coefficients, dermal exposure may be predicted using equilibrium data for compounds in equilibrium with cellulose and water, in combination with computational methods of predicting partition coefficients. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of Sulfuric Acid on the Uptake of Sulfur Dioxide on Soot

NASA Astrophysics Data System (ADS)

Slowik, J. G.; Koehler, B. G.

2001-05-01

The uptake of SO2 on soot may lead to the formation of sulfuric acid on the soot. The sulfuric acid then can affect the further uptake of SO2 on the soot. We are interested in the effect of submonolayer H2SO4 on the uptake of SO2. We measured the uptake of SO2 on n-hexane soot as a function SO2 pressure (10-7 to 10-4 Torr) and sulfuric acid coverage between -140\\deg and -120\\deg C. We generate sulfuric acid by adsorbing varying amounts of SO3 on soot, covering the SO3 with a thick layer of condensed H2O, and heating to 193 K to react the SO3 and H2O and to remove the excess H2O. The sulfuric acid coverage is in the range of monolayer or sub-monolayer. Adsorption of SO2 on soot with and without the sulfuric acid shows that the acid reduces the SO2 uptake by a factor of two or more. Varying the amount of acid has little effect on uptake. However, increasing the thickness of the soot substrate causes a significant increase in SO2 uptake.

Genetic identification of a gene involved in constitutive, high-affinity nitrate transport in higher plants.

PubMed Central

Wang, R; Crawford, N M

1996-01-01

Two mutations have been found in a gene (NRT2) of Arabidopsis thaliana that specifically impair constitutive, high-affinity nitrate uptake. These mutants were selected for resistance to 0.1 mM chlorate in the absence of nitrate. Progency from one of the backcrossed mutants showed no constitutive uptake of nitrate below 0.5 mM at pH 7.0 in liquid culture (that is, within 30 min of initial exposure to nitrate). All other uptake activities measured (high-affinity phosphate and sulfate uptake, inducible high-affinity nitrate uptake, and constitutive low-affinity nitrate uptake) were present or nearly normal in the backcrossed mutant. Electrophysiological analysis of individual root cells showed that the nrt2 mutant showed little response to 0.25 mM of nitrate, whereas NRT2 wild-type cells showed an initial depolarization followed by recovery. At 10 mM of nitrate both the mutant and wild-type cells displayed similar, strong electrical responses. These results indicate that NRT2 is a critical and perhaps necessary gene for constitutive, high-affinity nitrate uptake in Arabidopsis, but not for inducible, high-affinity nor constitutive, low-affinity nitrate uptake. Thus, these systems are genetically distinct. PMID:8799195

Uptake mechanism for iodine species to black carbon.

PubMed

Choung, Sungwook; Um, Wooyong; Kim, Minkyung; Kim, Min-Gyu

2013-09-17

Natural organic matter (NOM) plays an important role in determining the fate and transport of iodine species such as iodide (I(-)) and iodate (IO3(-)) in groundwater system. Although NOM exists as diverse forms in environments, prior iodine studies have mainly focused on uptake processes of iodide and iodate to humic materials. This study was conducted to determine the iodide and iodate uptake potential for a particulate NOM (i.e., black carbon [BC]). A laboratory-produced BC and commercial humic acid were used for batch experiments to compare their iodine uptake properties. The BC exhibited >100 times greater uptake capability for iodide than iodate at low pH of ~3, while iodide uptake was negligible for the humic acid. The uptake properties of both solids strongly depend on the initial iodine aqueous concentrations. After uptake reaction of iodide to the BC, X-ray absorption fine structure spectroscopy results indicated that the iodide was converted to electrophilic species, and iodine was covalently bound to carbon atom in polycyclic aromatic hydrocarbons present in the BC. The computed distribution coefficients (i.e., Kd values) suggest that the BC materials retard significantly the transport of iodide at low pH in environmental systems containing even a small amount of BC.

Non-rainfall water sources in the topsoil and their changes during formation of man-made algal crusts at the eastern edge of Qubqi Desert, Inner Mongolia.

PubMed

Lan, ShuBin; Hu, ChunXiang; Rao, BenQiang; Wu, Li; Zhang, DeLu; Liu, YongDing

2010-09-01

In arid and semiarid areas, water uptake (non-rainfall water) serves as an important water source for plants, biological soil crusts, insects and small animals. In this study, a measurement program was undertaken to investigate water uptake and its changes during formation of man-made algal crusts in the Qubqi Desert. In the study region, water uptake from the atmosphere accounted for 25.07%-39.83% of the total water uptake, and was mainly taken up by a water vapor adsorption mechanism; the proportion of water uptake from the soil substrate was much higher (60.17%-74.93%). The formation of crusts promoted water uptake, but the increased uptake did not occur immediately after inoculation or crusts formation. The water taken up from the atmosphere increased significantly from day 15 after inoculation, and the soil water content was markedly enhanced from day 20 after inoculation. It is considered that the growth of algal filaments and their secretions were the main factors increasing the amount of water uptake and water content in the crusts, and these variables increased even during dry periods when some algae are likely to have died.

Physiological expression of pancreatic somatostatin receptors in 99mTc-HYNIC-TOC scintigraphy.

PubMed

de la Cueva, L; Lloro, P; Sangrós, M J; López Vélez, L; Navarro, P; Sarria, L; Álvarez, S; Abós, D

2017-07-01

To describe the frequency of head and/or pancreas uncinate process uptake of 99mTc-HYNIC-TOC, to study its nature, and analyze its diagnostic value. Retrospective evaluation of 47 consecutive 99mTc-HYNIC-TOC examinations was conducted. Head and/or pancreas uncinate process uptake was considered to be physiological in patients with normal CT at the same episode and in follow-up. It was analyzed if age or diabetes mellitus was justifying the existence or not of uptake. 32.5% patients showed uptake; 73% of them were mild. 84.6% patients with uptake have no pathology and 4% had neuroendocrine pancreatic disease at CT. Neither the age nor the diabetes mellitus established differences in patients without lesion. Near one-third of patients show physiological uptake by head and/or pancreas uncinate process at 99mTc-HYNIC-TOC scintigraphy. It seems that neither the diabetes nor the ages are factors that determine this physiological uptake.

Lacrimal gland uptake of (67)Ga-gallium citrate correlates with biopsy results in patients with suspected sarcoidosis.

PubMed

Tannen, Bradford L; Kolomeyer, Anton M; Turbin, Roger E; Frohman, Larry; Langer, Paul D; Oh, Cheongeun; Ghesani, Nasrin V; Zuckier, Lionel S; Chu, David S

2014-02-01

To investigate whether lacrimal gland uptake on (67)Ga-gallium citrate scintigraphy correlates with histopathologic evidence of sarcoidosis. A retrospective, pilot study of 31 patients with suspected sarcoidosis who underwent gallium scintigraphy and lacrimal gland biopsy. Lacrimal gland gallium uptake was assessed by subjective visual scoring (SVS) and lacrimal uptake ratio (LUR). Eleven (36%) patients had lacrimal gland biopsies containing noncaseating granulomas. A statistically significant correlation was found between lacrimal gland gallium uptake and biopsy positivity using SVS (p = 0.03) or LUR (p = 0.01). Using SVS, biopsy positivity rate increased from 0 to 50% in patients with mild to intense uptake. Using LUR, biopsy positivity rate increased linearly as the ratio increased from 13% (LUR < 4) to 100% (LUR > 8). Lacrimal biopsy positivity rate significantly correlated with gallium uptake on scintigraphy. Both SVS and LUR methods appear to correlate with histologic results and may potentially aid in patient selection for biopsy.

[Postoperative uptake of Ga-67 in planar scintigraphy and SPECT after median sternotomy].

PubMed

Montero, A; Carril, J; Quirce, R; Gutiérrez Mendiguchía, C; Uriarte, I; Rabasa, J; Vallina, N K

1998-01-01

Surgical alterations after median sternotomy can difficult the interpretation of scintigraphic images with Ga67. To analize the use of Ga67 scintigraphy in this patology, we wanted to know the Ga67 distribution in patients who had suffered median sternotomy. We studied 8 patients in the first month after median sternotomy without infection complication and performed planar images and SPECT. Ga67 showed uptake in liver, spleen and bone. Sternal uptake was greater or lesser than liver uptake but always showed an homogeneous distribution. No mediastinum uptake was observed. Surgical wound showed Ga67 uptake during the first week after sternotomy. To know the distribution of Ga67 in patients after median sternotomy allows the scan interpretation when we suspect infectous complications.

Mechanism of uptake of nitrosoureas by L5178Y lymphoblasts in vitro.

PubMed

Begleiter, A; Lam, H P; Goldenberg, G J

1977-04-01

The mechanism of uptake of nitrosoureas by L5178Y cells in vitro was investigated. A time course of the uptake of radioactivity on incubation of L5178Y lymphoblast with [14C]-1,3-bis(2-chloroethyl)-1-nitrosourea was linear for 30 min and then entered a plateau phase; it was markedly temperature dependent. A similar time course for cells incubated with [14C]ethylene-labeled 1-(2-chlorethyl)-3-cyclohexyl-1-nitrosourea reached equilibrium rapidly, was temperature independent, and resulted in a relatively low level of uptake of radioactivity. However, cells treated with 3-[cyclohexyl-14C]-1-(2-chlorethyl)-1-nitrosourea had a time course that was linear for 30 min, resulted in much higher levels of uptake of radioactivity, and was strongly temperature dependent. These findings, at least for 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, suggest that some drug decomposition precedes uptake. The percentage of radioactivity found in the cell sap fraction was at least 85% of total cell activity when cells were incubated with any of the three 14C-labeled nitrosoureas. Furthermore, thin-layer chromatography of the cell sap fraction revealed the presence of free intact drug. These findings indicate that intracellular uptake of intact nitrosoureas occurred. A time course of uptake of intact 1,3-bis(2-chloroethyl)-1-nitrosourea reached equilibrium rapidly with cell/medium distribution ratios of 0.2 to 0.6 and was temperature independent. The addition of excess unlabeled 1,3-bis(2-chlorethyl)-1-nitrosourea or 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea had no effect on uptake of [14C]-1,3-bis(2-chloroethyl)-1-nitrosourea, These findings suggest that uptake of intact 1,3-bis(2-chloroethyl)-1-nitrosourea was by passive diffusion. A time course of the uptake of intact 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea with either [14C]ethylene- or ring-labeled drug rapidly reached equilibrium, was temperature independent, and attained a cell/medium ratio greater than unity. Uptake of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea was sodium independent and was unaffected by the metabolic inhibitors (sodium fluoride, sodium cyanide, or 2,4-dinitrophenol) or by urea, a potential physiological competitor. Furthermore, addition of unlabeled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea or 1,3-bis(2-chlorethyl)-1-nitrosourea had no effect on uptake of labeled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. These findings suggest that uptake of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea also occurs by passive diffusion.

Gastric gallium-67 uptake in gastritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, E.L.; Tisdale, P.L.; Zielonka, J.S.

1983-12-01

Even though Ga-67 imaging has been used widely in the diagnosis of malignant as well as inflammatory lesions, its uptake in the stomach has been reported in the literature mainly in gastric lymphoma and carcinoma. As shown in this case, intense gastric uptake of the radionuclide may be seen in common gastritis without malignancy. Perhaps the benign gastric uptake of Ga-67 deserves more emphasis.

Using Rising Limb Analysis to Estimate Uptake of Reactive Solutes in Advective and Transient Storage Sub-compartments of Stream Ecosystems

NASA Astrophysics Data System (ADS)

Thomas, S. A.; Valett, H.; Webster, J. R.; Mulholland, P. J.; Dahm, C. N.

2001-12-01

Identifying the locations and controls governing solute uptake is a recent area of focus in studies of stream biogeochemistry. We introduce a technique, rising limb analysis (RLA), to estimate areal nitrate uptake in the advective and transient storage (TS) zones of streams. RLA is an inverse approach that combines nutrient spiraling and transient storage modeling to calculate total uptake of reactive solutes and the fraction of uptake occurring within the advective sub-compartment of streams. The contribution of the transient storage zones to solute loss is determined by difference. Twelve-hour coinjections of conservative (Cl-) and reactive (15NO3) tracers were conducted seasonally in several headwater streams among which AS/A ranged from 0.01 - 2.0. TS characteristics were determined using an advection-dispersion model modified to include hydrologic exchange with a transient storage compartment. Whole-system uptake was determined by fitting the longitudinal pattern of NO3 to first-order, exponential decay model. Uptake in the advective sub-compartment was determined by collecting a temporal sequence of samples from a single location beginning with the arrival of the solute front and concluding with the onset of plateau conditions (i.e. the rising limb). Across the rising limb, 15NO3:Cl was regressed against the percentage of water that had resided in the transient storage zone (calculated from the TS modeling). The y-intercept thus provides an estimate of the plateau 15NO3:Cl ratio in the absence of NO3 uptake within the transient storage zone. Algebraic expressions were used to calculate the percentage of NO3 uptake occurring in the advective and transient storage sub-compartments. Application of RLA successfully estimated uptake coefficients for NO3 in the subsurface when the physical dimensions of that habitat were substantial (AS/A > 0.2) and when plateau conditions at the sampling location consisted of waters in which at least 25% had resided in the transient storage zone. In those cases, the TS zone accounted for 8 - 47 % of overall NO3 uptake and uptake rates within the subsurface ranged from 0.7 - 14.3 mg N m-2 d-1.

Linking Fruit Ca Uptake Capacity to Fruit Growth and Pedicel Anatomy, a Cross-Species Study

PubMed Central

Song, Wenpei; Yi, Junwen; Kurniadinata, Odit F.; Wang, Huicong; Huang, Xuming

2018-01-01

Calcium (Ca) in flesh fruits is important for quality formation and maintenance. Most studies on fruit Ca focus on one species. This study attempted to understand some universal relations to fruit Ca uptake across species. Calcium contents in fruit tissues were analyzed in different fruits, including three cultivars of litchi, two cultivars each of grape and citrus, and one cultivar each of loquat, apple, pear, Indian jujube, and longan. In situ Ca distribution was revealed with electron probe and xylem functionality visualized by dye tracing. Fruit Ca uptake rate and activity were calculated and correlated with fruit growth and pedicel anatomy. The results showed that fruit Ca uptake rate was the highest in pomes (loquat, apple, and pear), followed by Indian jujube drupe, arillate fruits (litchis and longan) and citrus, while grape berries were the lowest. Fruit Ca uptake rate showed a strong positive correlation to growth rate. However, Ca uptake activity, reflecting Ca uptake rate relative to growth, was the highest in arillate fruits and loquat and lowest in grape berries, and had a poor correlation with fruit growth rate. In all fruits, Ca concentration in the pedicel was higher than in the fruit, and they displayed a good positive correlation. In the pedicel, Ca was most abundant in the phloem. Dye tracing showed that xylem function loss occurred with maturation in all species/varieties. Apple had the poorest xylem functionality with the least development of secondary xylem, but its Ca uptake rate was among the highest. Vessel density, size and area in the pedicel showed no correlation with fruit Ca uptake rate. It is concluded that: (1) fruit growth may be a key determinant of Ca uptake; (2) the universal pattern of Ca being higher in the pedicel than in the fruit indicates existence of a pedicel-fruit “bottleneck” effect in Ca transport across species; (3) xylem functionality loss with fruit maturation is also a universal event; (4) in the pedicel, Ca is more distributed in the phloem; (5) vessel morphology in the pedicel is not rate-limiting for fruit Ca uptake; (6) phloem pathway might contribute to fruit Ca uptake. PMID:29868049

Influence of aerosol chemical composition on N2O5 uptake: airborne regional measurements in northwestern Europe

NASA Astrophysics Data System (ADS)

Morgan, W. T.; Ouyang, B.; Allan, J. D.; Aruffo, E.; Di Carlo, P.; Kennedy, O. J.; Lowe, D.; Flynn, M. J.; Rosenberg, P. D.; Williams, P. I.; Jones, R.; McFiggans, G. B.; Coe, H.

2015-01-01

Aerosol chemical composition was found to influence nighttime atmospheric chemistry during a series of airborne measurements in northwestern Europe in summer conditions, which has implications for regional air quality and climate. The uptake of dinitrogen pentoxide, γ (N2O5), to particle surfaces was found to be modulated by the amount of water content and ammonium nitrate present in the aerosol. The conditions prevalent in this study suggest that the net uptake rate of N2O5 to atmospheric aerosols was relatively efficient compared to previous studies, with γ (N2O5) values in the range 0.01-0.03. This is likely a consequence of the elevated relative humidity in the region, which promotes greater aerosol water content. Increased nitrate concentrations relative to particulate water were found to suppress N2O5 uptake. The results presented here contrast with previous ambient studies of N2O5 uptake, which have generally taken place in low-nitrate environments in the USA. Comparison of the N2O5 uptake derived from the measurements with a parameterised scheme that is based on the ratio of particulate water to nitrate yielded reasonably good agreement in terms of the magnitude and variation in uptake, provided the effect of chloride was neglected. An additional suppression of the parameterised uptake is likely required to fully capture the variation in N2O5 uptake, which could be achieved via the known suppression by organic aerosol. However, existing parameterisations representing the suppression by organic aerosol were unable to fully represent the variation in N2O5 uptake. These results provide important ambient measurement constraint on our ability to predict N2O5 uptake in regional and global aerosol models. N2O5 uptake is a potentially important source of nitrate aerosol and a sink of the nitrate radical, which is the main nocturnal oxidant in the atmosphere. The results further highlight the importance of ammonium nitrate in northwestern Europe as a key component of atmospheric composition in the region.

Influence of aerosol chemical composition on N2O5 uptake: airborne regional measurements in North-Western Europe

NASA Astrophysics Data System (ADS)

Morgan, W. T.; Ouyang, B.; Allan, J. D.; Aruffo, E.; Di Carlo, P.; Kennedy, O. J.; Lowe, D.; Flynn, M. J.; Rosenberg, P. D.; Williams, P. I.; Jones, R.; McFiggans, G. B.; Coe, H.

2014-07-01

Aerosol chemical composition was found to influence nighttime atmospheric chemistry during a series of airborne measurements in North-Western Europe in summer conditions, which has implications for regional air quality and climate. The uptake of dinitrogen pentoxide, γ (N2O5), to particle surfaces was found to be modulated by the amount of water content and ammonium nitrate present in the aerosol. The conditions prevalent in this study suggest that the net uptake rate of N2O5 to atmospheric aerosols was relatively efficient compared to previous studies, with γ (N2O5) values in the range 0.01-0.03. This is likely a consequence of the elevated relative humidity in the region, which promotes greater aerosol water content. Increased nitrate concentrations relative to particulate water were found to suppress N2O5 uptake. The results presented here contrast with previous ambient studies of N2O5 uptake, which have generally taken place in low-nitrate environments in the USA. Comparison of the N2O5 uptake derived from the measurements with a parameterised scheme that is based on the ratio of particulate water to nitrate yielded reasonably good agreement in terms of the magnitude and variation in uptake, provided the effect of chloride was neglected. An additional suppression of the parameterised uptake is likely required to fully capture the variation in N2O5 uptake, which could be achieved via the known suppression by organic aerosol. However, existing parameterisations representing the suppression by organic aerosol were unable to fully represent the variation in N2O5 uptake. These results provide important ambient measurement constraint on our ability to predict N2O5 uptake in regional and global aerosol models. N2O5 uptake is a potentially important source of nitrate aerosol and a sink of the nitrate radical, which is the main nocturnal oxidant in the atmosphere. The results further highlight the importance of ammonium nitrate in North-Western Europe as a key component of atmospheric composition in the region.

Bioaccumulation of total mercury in the earthworm Eisenia andrei.

PubMed

Le Roux, Shirley; Baker, Priscilla; Crouch, Andrew

2016-01-01

Earthworms are a major part of the total biomass of soil fauna and play a vital role in soil maintenance. They process large amounts of plant and soil material and can accumulate many pollutants that may be present in the soil. Earthworms have been explored as bioaccumulators for many heavy metal species such as Pb, Cu and Zn but limited information is available for mercury uptake and bioaccumulation in earthworms and very few report on the factors that influence the kinetics of Hg uptake by earthworms. It is known however that the uptake of Hg is strongly influenced by the presence of organic matter, hence the influence of ligands are a major factor contributing to the kinetics of mercury uptake in biosystems. In this work we have focused on the uptake of mercury by earthworms (Eisenia andrei) in the presence of humic acid (HA) under varying physical conditions of pH and temperature, done to assess the role of humic acid in the bioaccumulation of mercury by earthworms from soils. The study was conducted over a 5-day uptake period and all earthworm samples were analysed by direct mercury analysis. Mercury distribution profiles as a function of time, bioaccumulation factors (BAFs), first order rate constants and body burden constants for mercury uptake under selected conditions of temperature, pH as well as via the dermal and gut route were evaluated in one comprehensive approach. The results showed that the uptake of Hg was influenced by pH, temperature and the presence of HA. Uptake of Hg(2+) was improved at low pH and temperature when the earthworms in soil were in contact with a saturating aqueous phase. The total amount of Hg(2+) uptake decreased from 75 to 48 % as a function of pH. For earthworms in dry soil, the uptake was strongly influenced by the presence of the ligand. Calculated BAF values ranged from 0.1 to 0.8. Mercury uptake typically followed first order kinetics with rate constants determined as 0.2 to 1 h(-1).

Sodium-dependent magnesium uptake by ferret red cells.

PubMed Central

Flatman, P W; Smith, L M

1991-01-01

1. Magnesium uptake can be measured in ferret red cells incubated in media containing more than 1 mM-magnesium. Uptake is substantially increased if the sodium concentration in the medium is reduced. 2. Magnesium uptake is half-maximally activated by 0.37 mM-external magnesium when the external sodium concentration is 5 mM. Increasing the external sodium concentration increases the magnesium concentration needed to activate the system. 3. Magnesium uptake is increased by reducing the external sodium concentration. Uptake is half-maximum at sodium concentrations of 17, 22 and 62 nM when the external magnesium concentrations are 2, 5 and 10 mM respectively. 4. Replacement of external sodium with choline does not affect the membrane potential of ferret red cells over a 45 min period. 5. Magnesium uptake from media containing 5 mM-sodium is inhibited by amiloride, quinidine and imipramine. It is not affected by ouabain or bumetanide. Vanadate stimulates magnesium uptake but has no effect on magnesium efflux. 6. When cell ATP content is reduced to 19 mumol (1 cell)-1 by incubating cells for 3 h with 2-deoxyglucose, magnesium uptake falls by 50% in the presence of 5 mM-sodium and is completely abolished in the presence of 145 mM-sodium. Some of the inhibition may be due to the increase in intracellular ionized magnesium concentration ([Mg2+]i) from 0.7 to 1.0 mM which occurs under these conditions. 7. Magnesium uptake can be driven against a substantial electrochemical gradient if the external sodium concentration is reduced sufficiently. 8. These findings are discussed in terms of several possible models for magnesium transport. It is concluded that the majority of magnesium uptake observed in low-sodium media is via sodium-magnesium antiport. A small portion of uptake is through a parallel leak pathway. It is believed that the antiport is responsible for maintaining [Mg2+]i below electrochemical equilibrium in these cells at physiological external sodium concentration. Thus in ferret red cells the direction of magnesium transport can be reversed by reversing the sodium gradient. PMID:1822527

The interrelationship between muscle oxygenation, muscle activation, and pulmonary oxygen uptake to incremental ramp exercise: influence of aerobic fitness.

PubMed

Boone, Jan; Barstow, Thomas J; Celie, Bert; Prieur, Fabrice; Bourgois, Jan

2016-01-01

We investigated whether muscle and ventilatory responses to incremental ramp exercise would be influenced by aerobic fitness status by means of a cross-sectional study with a large subject population. Sixty-four male students (age: 21.2 ± 3.2 years) with a heterogeneous peak oxygen uptake (51.9 ± 6.3 mL·min(-1)·kg(-1), range 39.7-66.2 mL·min(-1)·kg(-1)) performed an incremental ramp cycle test (20-35 W·min(-1)) to exhaustion. Breath-by-breath gas exchange was recorded, and muscle activation and oxygenation were measured with surface electromyography and near-infrared spectroscopy, respectively. The integrated electromyography (iEMG), mean power frequency (MPF), deoxygenated [hemoglobin and myoglobin] (deoxy[Hb+Mb]), and total[Hb+Mb] responses were set out as functions of work rate and fitted with a double linear function. The respiratory compensation point (RCP) was compared and correlated with the breakpoints (BPs) (as percentage of peak oxygen uptake) in muscle activation and oxygenation. The BP in total[Hb+Mb] (83.2% ± 3.0% peak oxygen uptake) preceded (P < 0.001) the BP in iEMG (86.7% ± 4.0% peak oxygen uptake) and MPF (86.3% ± 4.1% peak oxygen uptake), which in turn preceded (P < 0.01) the BP in deoxy[Hb+Mb] (88.2% ± 4.5% peak oxygen uptake) and RCP (87.4% ± 4.5% peak oxygen uptake). Furthermore, the peak oxygen uptake was significantly (P < 0.001) positively correlated to the BPs and RCP, indicating that the BPs in total[Hb+Mb] (r = 0.66; P < 0.001), deoxy[Hb+Mb] (r = 0.76; P < 0.001), iEMG (r = 0.61; P < 0.001), MPF (r = 0.63; P < 0.001), and RCP (r = 0.75; P < 0.001) occurred at a higher percentage of peak oxygen uptake in subjects with a higher peak oxygen uptake. In this study a close relationship between muscle oxygenation, activation, and pulmonary oxygen uptake was found, occurring in a cascade of events. In subjects with a higher aerobic fitness level this cascade occurred at a higher relative intensity.

Sphagnum Mosses - Masters of Efficient N-Uptake while Avoiding Intoxication

PubMed Central

Fritz, Christian; Lamers, Leon P. M.; Riaz, Muhammad; van den Berg, Leon J. L.; Elzenga, Theo J. T. M.

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form (15N - ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5–6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands. PMID:24416125

OXYGEN UPTAKE BEFORE AND AFTER THE ONSET OF CLAUDICATION DURING A 6-MINUTE WALK TEST

PubMed Central

Gardner, Andrew W.; Ritti-Dias, Raphael M.; Stoner, Julie A.; Montgomery, Polly S.; Khurana, Aman; Blevins, Steve M.

2011-01-01

Purposes To compare oxygen uptake before and after the onset of claudication in subjects with peripheral artery disease (PAD) during a 6-minute walk test, and to identify predictors of the change in oxygen uptake following the onset of claudication pain Methods Fifty subjects with PAD were studied, in which 33 experienced claudication (Pain Group) during a 6-minute walk test, and 17 were pain-free during this test (Pain-Free Group). Oxygen uptake and ambulatory cadence were primary outcomes obtained during the 6-minute walk test. Results The Pain Group experienced onset of claudication pain at 179 ± 45 meters (mean ± standard deviation) and continued to walk to achieve a 6-minute walk distance of 393 ± 74 meters, which was similar (p = 0.74) to the Pain-Free Group (401 ± 76 meters). Oxygen uptake increased (p < 0.0001) after the onset of pain in the Pain Group, and this change was greater (p = 0.025) than the increase in oxygen uptake from the second to fifth minute of walking in the Pain-Free Group. Furthermore, ambulatory cadence decreased after the onset of pain in the Pain Group (p = 0.0003). The change in oxygen uptake was associated with metabolic syndrome (p = 0.0023), 6-minute walk distance (p = 0.0037), age, (p = 0.0041), and the oxygen uptake during the second minute of the test (p = 0.012). Conclusion Claudication increases oxygen uptake of self-paced, over-ground ambulation despite a decrease in cadence. The pain-mediated increase in oxygen uptake was blunted in subjects with metabolic syndrome, suggesting that they have an impaired ability to increase oxygen uptake during ambulation. The clinical significance is that claudication increases metabolic cost of ambulation, thereby increasing the relative intensity of exercise and reducing the tolerance to sustain ambulation. PMID:21890308

Differences in uptake of immunisations and health examinations among refugee children compared to Danish-born children: a cohort study.

PubMed

Moller, Sanne Pagh; Hjern, Anders; Andersen, Anne-Marie Nybo; Norredam, Marie

2016-04-01

Refugee children and their families constitute a vulnerable group regarding health and access to care. In a register-based cohort design, we examined differences in uptake of immunisations and child health examinations between refugee children and Danish-born children, including predictors of uptake among refugee children. Refugee children (n = 16,701) who, between January 1993 and December 2010, obtained residency permits in Denmark were included and matched in a 1:6 ratio on age and sex with Danish-born children (n = 100,206). Personal identification numbers were cross-linked to the National Danish Health Service Register, identifying all contacts for immunisation and child health examinations. We estimated hazard ratios (HR) of uptake. Refugee children had a lower uptake of all immunisations compared to Danish-born children. The lowest uptake was found for immunisation against diphtheria, tetanus, pertussis and polio (HR = 0.50; 95 % confidence interval (CI) 0.48-0.51). Participation in child health examinations was also lower among refugee children with the lowest at the last child health examination at age 5 (HR = 0.48; 95 % CI 0.47-0.50). Adjusting the analysis for parental income increased the HRs by 10-20 %. This Danish register-based study using nationwide data revealed a lower uptake of routine immunisations and child health examinations among refugee children compared to Danish-born children. •Uptake of immunisation and child health examination is associated with low household income, unemployment and low educational status among the parents. •Uptake may be even lower among refugee families as they constitute a vulnerable group regarding access to healthcare. What is New: •Refugee children had lower uptake of immunisations and child health examinations compared to Danish-born children. •Several predictors of uptake were identified including region of origin and duration of residence.

Modelling Water Uptake Provides a New Perspective on Grass and Tree Coexistence

PubMed Central

2015-01-01

Root biomass distributions have long been used to infer patterns of resource uptake. These patterns are used to understand plant growth, plant coexistence and water budgets. Root biomass, however, may be a poor indicator of resource uptake because large roots typically do not absorb water, fine roots do not absorb water from dry soils and roots of different species can be difficult to differentiate. In a sub-tropical savanna, Kruger Park, South Africa, we used a hydrologic tracer experiment to describe the abundance of active grass and tree roots across the soil profile. We then used this tracer data to parameterize a water movement model (Hydrus 1D). The model accounted for water availability and estimated grass and tree water uptake by depth over a growing season. Most root biomass was found in shallow soils (0–20 cm) and tracer data revealed that, within these shallow depths, half of active grass roots were in the top 12 cm while half of active tree roots were in the top 21 cm. However, because shallow soils provided roots with less water than deep soils (20–90 cm), the water movement model indicated that grass and tree water uptake was twice as deep as would be predicted from root biomass or tracer data alone: half of grass and tree water uptake occurred in the top 23 and 43 cm, respectively. Niche partitioning was also greater when estimated from water uptake rather than tracer uptake. Contrary to long-standing assumptions, shallow grass root distributions absorbed 32% less water than slightly deeper tree root distributions when grasses and trees were assumed to have equal water demands. Quantifying water uptake revealed deeper soil water uptake, greater niche partitioning and greater benefits of deep roots than would be estimated from root biomass or tracer uptake data alone. PMID:26633177

Role of ethnicity in human papillomavirus vaccination uptake: a cross-sectional study of girls from ethnic minority groups attending London schools

PubMed Central

Rockliffe, Lauren; Waller, Jo; Marlow, Laura A V; Forster, Alice S

2017-01-01

Objectives Research suggests that girls from ethnic minority groups are less likely to receive the human papillomavirus (HPV) vaccination than white British girls; however, the specific ethnic minority groups that have lower uptake have not been identified. This study aimed to examine the relationship between school-level uptake and ethnicity as well as uptake and other ethnicity-related factors, to understand which specific groups are less likely to receive the vaccination. Methods Aggregated uptake rates from 195 schools were obtained for each of the three recommended vaccine doses from 2008 to 2010. Census data at the lower super output area (LSOA) level for the postcode of each school were also obtained, describing the ethnic breakdown of the resident population (ethnicity, language spoken, religion, proficiency in English and duration of residency in the UK). These were used as proxy measures of the ethnic make-up of the schools. The most prevalent non-majority group for each ethnicity and ethnicity-related factor was assigned to each school. Analyses explored differences in uptake by ethnicity and ethnicity-related factors. Results No significant differences in vaccination uptake were found by ethnicity or ethnicity-related factors, although descriptive differences were apparent. Schools in areas where black ethnicities were the most prevalent non-white British ethnicities had consistently low rates of uptake for all doses. Schools in areas where some Asian ethnicities were the most prevalent non-white British ethnicities had consistently high rates of uptake for all doses. There was evidence of variability in mean uptake rates for ethnicities within ‘black’ and ‘Asian’ ethnic groups. Conclusions Future research would benefit from focusing on specific ethnicities rather than broad ethnic categories. Replication of this study with a larger sample and using complete individual-level data, collected on a national level, would provide a clearer indication of where ethnic differences in HPV vaccination uptake exist. PMID:28235971

Sphagnum mosses--masters of efficient N-uptake while avoiding intoxication.

PubMed

Fritz, Christian; Lamers, Leon P M; Riaz, Muhammad; van den Berg, Leon J L; Elzenga, Theo J T M

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form ((15)N-ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5-6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands.

Maple sap uptake, exudation, and pressure changes correlated with freezing exotherms and thawing endotherms.

PubMed

Tyree, M T

1983-10-01

Sap flow rates and sap pressure changes were measured in dormant sugar maple trees (Acer saccharum Marsh.). In the forest, sap flow rates and pressure changes were measured from tap holes drilled into tree trunks in mature trees and sap flow rates were measured from the base of excised branches. Excised branches were also brought into the laboratory where air temperature could be carefully controlled in a refrigerated box and sap flow rates and sap pressures were measured from the cut base of the branches.Under both forest and laboratory conditions, sap uptake occurred as the wood temperature declined but much more rapid sap uptake correlated with the onset of the freezing exotherm. When sap pressures were measured under conditions of negligible volume displacement, the sap pressure rapidly fell to -60 to -80 kilopascals at the start of the freezing exotherm. The volume of water uptake and the rate of uptake depended on the rate of freezing. A slow freezing rate correlated with a large volume of water uptake, a fast freezing rate induced a smaller volume of water uptake. The volume of water uptake ranged from 0.02 to 0.055 grams water per gram dry weight of sapwood. The volume of water exuded after thawing was usually less than the volume of uptake so that after several freezing and thawing cycles the sapwood water content increased from 0.7 to 0.8 grams water per gram dry weight.These results are discussed in terms of a physical model of the mechanism of maple sap uptake and exudation first proposed by P. E. R. O'Malley. The proposed mechanism of sap uptake is by vapor distillation in air filled wood fiber lumina during the freezing of minor branches. Gravity and pressurized air bubbles (compressed during freezing) cause sap flow from the canopy down the tree after the thaw.

Maple Sap Uptake, Exudation, and Pressure Changes Correlated with Freezing Exotherms and Thawing Endotherms 1

PubMed Central

Tyree, Melvin T.

1983-01-01

Sap flow rates and sap pressure changes were measured in dormant sugar maple trees (Acer saccharum Marsh.). In the forest, sap flow rates and pressure changes were measured from tap holes drilled into tree trunks in mature trees and sap flow rates were measured from the base of excised branches. Excised branches were also brought into the laboratory where air temperature could be carefully controlled in a refrigerated box and sap flow rates and sap pressures were measured from the cut base of the branches. Under both forest and laboratory conditions, sap uptake occurred as the wood temperature declined but much more rapid sap uptake correlated with the onset of the freezing exotherm. When sap pressures were measured under conditions of negligible volume displacement, the sap pressure rapidly fell to −60 to −80 kilopascals at the start of the freezing exotherm. The volume of water uptake and the rate of uptake depended on the rate of freezing. A slow freezing rate correlated with a large volume of water uptake, a fast freezing rate induced a smaller volume of water uptake. The volume of water uptake ranged from 0.02 to 0.055 grams water per gram dry weight of sapwood. The volume of water exuded after thawing was usually less than the volume of uptake so that after several freezing and thawing cycles the sapwood water content increased from 0.7 to 0.8 grams water per gram dry weight. These results are discussed in terms of a physical model of the mechanism of maple sap uptake and exudation first proposed by P. E. R. O'Malley. The proposed mechanism of sap uptake is by vapor distillation in air filled wood fiber lumina during the freezing of minor branches. Gravity and pressurized air bubbles (compressed during freezing) cause sap flow from the canopy down the tree after the thaw. PMID:16663208

Effects of residence time on summer nitrate uptake in Mississippi River flow-regulated backwaters

USGS Publications Warehouse

James, W.F.; Richardson, W.B.; Soballe, D.M.

2008-01-01

Nitrate uptake may be improved in regulated floodplain rivers by increasing hydrological connectivity to backwaters. We examined summer nitrate uptake in a series of morphologically similar backwaters on the Upper Mississippi River receiving flow-regulated nitrate loads via gated culverts. Flows into individual backwaters were held constant over a summer period but varied in the summers of 2003 and 2004 to provide a range of hydraulic loads and residence times (??). The objectives were to determine optimum loading and ?? for maximum summer uptake. Higher flow adjustment led to increased loading but lower ?? and contact time for uptake. For highest flows, ?? was less than 1 day resulting in lower uptake rates (Unet, 4000 m). For low flows, ?? was greater than 5 days and U% approached 100%, but Unet was 200 mg m-2 day-1. Snet was < half the length of the backwaters under these conditions indicating that most of the load was assimilated in the upper reaches, leading to limited delivery to lower portions. Unet was maximal (384-629 mg m-2 day-1) for intermediate flows and ?? ranging between 1 and 1.5 days. Longer Snet (2000-4000 m) and lower U% (20-40%) reflected limitation of uptake in upper reaches by contact time, leading to transport to lower reaches for additional uptake. Uptake by ???10 000 ha of reconnected backwaters along the Upper Mississippi River (13% of the total backwater surface area) at a Unet of ???630 mg m-2 day-1 would be the equivalent of ???40% of the summer nitrate load (155 mg day-1) discharged from Lock and Dam 4. These results indicate that backwater nitrate uptake can play an important role in reducing nitrate loading to the Gulf of Mexico. Copyright ?? 2008 John Wiley & Sons, Ltd.

A Comparative Study of Iron Uptake Mechanisms in Marine Microalgae: Iron Binding at the Cell Surface Is a Critical Step1[W][OA

PubMed Central

Sutak, Robert; Botebol, Hugo; Blaiseau, Pierre-Louis; Léger, Thibaut; Bouget, François-Yves; Camadro, Jean-Michel; Lesuisse, Emmanuel

2012-01-01

We investigated iron uptake mechanisms in five marine microalgae from different ecologically important phyla: the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana, the prasinophyceae Ostreococcus tauri and Micromonas pusilla, and the coccolithophore Emiliania huxleyi. Among these species, only the two diatoms were clearly able to reduce iron, via an inducible (P. tricornutum) or constitutive (T. pseudonana) ferrireductase system displaying characteristics similar to the yeast (Saccharomyces cerevisiae) flavohemoproteins proteins. Iron uptake mechanisms probably involve very different components according to the species, but the species we studied shared common features. Regardless of the presence and/or induction of a ferrireductase system, all the species were able to take up both ferric and ferrous iron, and iron reduction was not a prerequisite for uptake. Iron uptake decreased with increasing the affinity constants of iron-ligand complexes and with increasing ligand-iron ratios. Therefore, at least one step of the iron uptake mechanism involves a thermodynamically controlled process. Another step escapes to simple thermodynamic rules and involves specific and strong binding of ferric as well as ferrous iron at the cell surface before uptake of iron. Binding was paradoxically increased in iron-rich conditions, whereas uptake per se was induced in all species only after prolonged iron deprivation. We sought cell proteins loaded with iron following iron uptake. One such protein in O. tauri may be ferritin, and in P. tricornutum, Isip1 may be involved. We conclude that the species we studied have uptake systems for both ferric and ferrous iron, both involving specific iron binding at the cell surface. PMID:23033141

Usefulness and pitfalls of MAA SPECT/CT in identifying digestive extrahepatic uptake when planning liver radioembolization.

PubMed

Lenoir, Laurence; Edeline, Julien; Rolland, Yann; Pracht, Marc; Raoul, Jean-Luc; Ardisson, Valérie; Bourguet, Patrick; Clément, Bruno; Boucher, Eveline; Garin, Etienne

2012-05-01

Identifying gastroduodenal uptake of (99m)Tc-macroaggregated albumin (MAA), which is associated with an increased risk of ulcer disease, is a crucial part of the therapeutic management of patients undergoing radioembolization for liver tumours. Given this context, the use of MAA single photon emission computed tomography (SPECT)/CT may be essential, but the procedure has still not been thoroughly evaluated. The aim of this retrospective study was to determine the effectiveness of MAA SPECT/CT in identifying digestive extrahepatic uptake, while determining potential diagnostic pitfalls. Overall, 139 MAA SPECT/CT scans were performed on 103 patients with different hepatic tumour types. Patients were followed up for at least 6 months according to standard requirements. Digestive, or digestive-like, uptake other than free pertechnetate was identified in 5.7% of cases using planar imaging and in 36.6% of cases using SPECT/CT. Uptake sites identified by SPECT/CT included the gastroduodenal region (3.6%), gall bladder (12.2%), portal vein thrombosis (6.5%), hepatic artery (6.5%), coil embolization site (2.1%) as well as falciform artery (5.0%). For 2.1% of explorations, a coregistration error between SPECT and CT imaging could have led to a false diagnosis by erroneously attributing an uptake site to the stomach or gall bladder, when the uptake actually occurred in the liver. SPECT/CT is more efficacious than planar imaging in identifying digestive extrahepatic uptake sites, with extrahepatic uptake observed in one third of scans using the former procedure. However, more than half of the uptake sites in our study were vascular in nature, without therapeutic implications. The risk of coregistration errors must also be kept in mind.

18F-FDG uptake in the colon is modulated by metformin but not associated with core body temperature and energy expenditure

PubMed Central

Bahler, Lonneke; Holleman, Frits; Chan, Man-Wai; Booij, Jan; Hoekstra, Joost B.; Verberne, Hein J.

2017-01-01

Purpose Physiological colonic 18F-fluorodeoxyglucose (18F-FDG) uptake is a frequent finding on 18F-FDG positron emission tomography computed tomography (PET-CT). Interestingly, metformin, a glucose lowering drug associated with moderate weight loss, is also associated with an increased colonic 18F-FDG uptake. Consequently, increased colonic glucose use might partly explain the weight losing effect of metformin when this results in an increased energy expenditure and/or core body temperature. Therefore, we aimed to determine whether metformin modifies the metabolic activity of the colon by increasing glucose uptake. Methods In this open label, non-randomized, prospective mechanistic study, we included eight lean and eight overweight males. We measured colonic 18F-FDG uptake on PET-CT, energy expenditure and core body temperature before and after the use of metformin. The maximal colonic 18F-FDG uptake was measured in 5 separate segments (caecum, colon ascendens,—transversum,—descendens and sigmoid). Results The maximal colonic 18F-FDG uptake increased significantly in all separate segments after the use of metformin. There was no significant difference in energy expenditure or core body temperature after the use of metformin. There was no correlation between maximal colonic 18F-FDG uptake and energy expenditure or core body temperature. Conclusion Metformin significantly increases colonic 18F-FDG uptake, but this increased uptake is not associated with an increase in energy expenditure or core body temperature. Although the colon might be an important site of the glucose plasma lowering actions of metformin, this mechanism of action does not explain directly any associated weight loss. PMID:28464031

Meta-[{sup 211}At]astatobenzylguanidine (MABG): In vivo evaluation in an athymic mouse human neuroblastoma xenograft model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vaidyanathan, G.; Friedman, H.S.; Keir, S.T.

1996-05-01

Because of the short range and high linear energy transfer of {sup 211}At {alpha}-particles, the MIBG analogue MABG might be useful for the therapy of micrometastatic neuroblastoma and previous in vitro studies have demonstrated that under single-cell conditions, the cytotoxicity of MABG is > 1000 times higher than [{sup 131}I]MIBG. A paired label protocol was used to compare the tissue distribution of MABG and [{sup 131}I]MIBG in athymic mice bearing subcutaneous SK-N-SH human neuroblastoma xenografts from 1-24 hr after injection. In tumor, significantly higher (p < 0.05) uptake was observed for MABG (3.8 {plus_minus} 0.8%ID/g vs 3.1 {plus_minus} 0.7%ID/g atmore » 8 hr). Pretreatment with desipramine reduced tumor uptake of MABG by 43%, suggesting that accumulation was related to the uptake-1 mechanism. Significantly higher uptake of MABG also was observed in normal tissue targets. For example, at 8 hr, heart uptake of MABG was 6.0 {plus_minus} 0.9 % ID/g compared with 4.5 {plus_minus} 0.8%ID/g for [{sup 131}I]MIBG. Two strategies were investigated to increase the tumor-to-hear uptake ratio. Pretreatment of mice with unlabeled MIBG (4 mg/kg) increased MABG tumor uptake by 1.5-fold while reducing uptake in several normal tissues including heart. The vesicular uptake blocker tetrabenazine (TBZ; 20 mg/kg), reduced MABG hear uptake by 30% of control values with not significant decrease in tumor levels. We conclude that MABG deserves further evaluation as a potential agent for the treatment of neuroblastoma, particularly in combination with strategies to minimize radiation dose to normal target tissues.« less

Tau Antibody Targeting Pathological Species Blocks Neuronal Uptake and Interneuron Propagation of Tau in Vitro.

PubMed

Nobuhara, Chloe K; DeVos, Sarah L; Commins, Caitlin; Wegmann, Susanne; Moore, Benjamin D; Roe, Allyson D; Costantino, Isabel; Frosch, Matthew P; Pitstick, Rose; Carlson, George A; Hock, Christoph; Nitsch, Roger M; Montrasio, Fabio; Grimm, Jan; Cheung, Anne E; Dunah, Anthone W; Wittmann, Marion; Bussiere, Thierry; Weinreb, Paul H; Hyman, Bradley T; Takeda, Shuko

2017-06-01

The clinical progression of Alzheimer disease (AD) is associated with the accumulation of tau neurofibrillary tangles, which may spread throughout the cortex by interneuronal tau transfer. If so, targeting extracellular tau species may slow the spreading of tau pathology and possibly cognitive decline. To identify suitable target epitopes, we tested the effects of a panel of tau antibodies on neuronal uptake and aggregation in vitro. Immunodepletion was performed on brain extract from tau-transgenic mice and postmortem AD brain and added to a sensitive fluorescence resonance energy transfer-based tau uptake assay to assess blocking efficacy. The antibodies reduced tau uptake in an epitope-dependent manner: N-terminal (Tau13) and middomain (6C5 and HT7) antibodies successfully prevented uptake of tau species, whereas the distal C-terminal-specific antibody (Tau46) had little effect. Phosphorylation-dependent (40E8 and p396) and C-terminal half (4E4) tau antibodies also reduced tau uptake despite removing less total tau by immunodepletion, suggesting specific interactions with species involved in uptake. Among the seven antibodies evaluated, 6C5 most efficiently blocked uptake and subsequent aggregation. More important, 6C5 also blocked neuron-to-neuron spreading of tau in a unique three-chamber microfluidic device. Furthermore, 6C5 slowed down the progression of tau aggregation even after uptake had begun. Our results imply that not all antibodies/epitopes are equally robust in terms of blocking tau uptake of human AD-derived tau species. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Longitudinal observation of [11C]4DST uptake in turpentine-induced inflammatory tissue.

PubMed

Toyohara, Jun; Sakata, Muneyuki; Oda, Keiichi; Ishii, Kenji; Ishiwata, Kiichi

2013-02-01

Longitudinal changes of 4'-[methyl-(11)C]thiothymidine ([(11)C]4DST) uptake were evaluated in turpentine-induced inflammation. Turpentine (0.1 ml) was injected intramuscularly into the right hind leg of male Wistar rats. Longitudinal [(11)C]4DST uptake was evaluated by the tissue dissection method at 1, 2, 4, 7, and 14 days after turpentine injection (n=5). The tumor selectivity index was calculated using the previously published biodistribution data in C6 glioma-bearing rats. Dynamic PET scan was performed on day 4 when maximum [(11)C]4DST uptake was observed during the longitudinal study. Histopathological analysis and Ki-67 immunostaining were also performed. The uptake of [(11)C]4DST in inflammatory tissue was significantly increased on days 2-4 after turpentine injection, and then decreased. On day 14, tracer uptake returned to the day 1 level. The maximum SUV of inflamed muscle was 0.6 and was 3 times higher than that of the contralateral healthy muscle on days 2-4 after turpentine injection. However, tumor selectivity index remains very high (>10) because of the low inflammation uptake. A dynamic PET scan showed that the radioactivity in inflammatory tissues peaked at 5 min after [(11)C]4DST injection, and then washed out until 20 min. At intervals >20 min, radioactivity levels were constant and double that of healthy muscle. The changes in Ki-67 index were paralleled with those of [(11)C]4DST uptake, indicating cell proliferation-dependent uptake of [(11)C]4DST in inflammatory tissues. In our animal model, low but significant levels of [(11)C]4DST uptake were observed in subacute inflammation. Copyright © 2013 Elsevier Inc. All rights reserved.

123I-MIBG cardiac uptake and smell identification in parkinsonian patients with LRRK2 mutations.

PubMed

Valldeoriola, Francesc; Gaig, Carles; Muxí, Africa; Navales, Ignacio; Paredes, Pilar; Lomeña, Francisco; De la Cerda, Andres; Buongiorno, Mariateresa; Ezquerra, Mario; Santacruz, Pilar; Martí, Maria Jose; Tolosa, Eduardo

2011-06-01

Reduced uptake of (123)I- metaiodobenzylguanidine (MIBG) on cardiac gammagraphy and impaired odor identification are markers of neurodegenerative diseases with Lewy bodies (LB) as a pathological hallmark, such as idiopathic Parkinson's disease (IPD). LRRK2 patients present with a clinical syndrome indistinguishable from IPD, but LB have not been found in some cases. Patients with such mutations could behave differently than patients with IPD with respect to MIBG cardiac uptake and olfaction. We studied 14 LRRK2 patients, 14 IPD patients matched by age, gender, disease duration and severity, and 13 age and gender matched control subjects. Olfaction was analyzed through the University of Pennsylvania Smell Identification Test (UPSIT). MIBG cardiac uptake was evaluated through the H/M ratio. The late H/M was 1.44 ± 0.31 for LRRK2 patients, 1.19 ± 0.15 for PD patients, and 1.67 ± 0.16 for control subjects. LRRK2 patients presented lower but not statistically significant MIBG cardiac uptake than controls (p = 0.08) and significant higher uptake than PD patients (p = 0.04). UPSIT mean scores were 21.5 ± 7.3 for LRRK2 patients, 18.7 ± 6.2 for IPD patients and 29.7 ± 5.7 for control subjects. UPSIT score was lower in both LRRK2 and PD than in controls. In LRRK2 patients a positive correlation was found between myocardial MIBG uptake and UPSIT scores, (R = 0.801, p < 0.001). In LRRK2 patients, MIBG cardiac uptake was less impaired than in PD; a positive correlation between MIBG cardiac uptake and UPSIT scores was observed. As MIBG cardiac reduced uptake and impaired odor identification are markers of LB pathology, this findings may represent neuropathological heterogeneity among LRRK2 patients.

Contributions of system A subtypes to α-methylaminoisobutyric acid uptake by placental microvillous membranes of human and rat.

PubMed

Takahashi, Yu; Nishimura, Tomohiro; Maruyama, Tetsuo; Tomi, Masatoshi; Nakashima, Emi

2017-04-01

System A consists of three subtypes, sodium-coupled neutral amino acid transporter 1 (SNAT1), SNAT2, and SNAT4, which are all expressed in the placenta. The aim of this study was to evaluate the contributions of each of the three subtypes to total system A-mediated uptake in placental MVM of human and rat, using betaine and L-arginine as subtype-selective inhibitors of SNAT2 and SNAT4, respectively. Appropriate concentrations of betaine and L-arginine for subtype-selective inhibition in SNAT-overexpressing cells were identified. It was found that 10 mM betaine specifically and almost completely inhibited human and rat SNAT2-mediated [ 14 C]α-methylaminoisobutyric acid ([ 14 C]MeAIB) uptake, while 5 mM L-arginine specifically and completely inhibited [ 3 H]glycine uptake via human SNAT4, as well as [ 14 C]MeAIB uptake via rat SNAT4. In both human and rat placental MVM vesicles, sodium-dependent uptake of [ 14 C]MeAIB was almost completely inhibited by 20 mM unlabeled MeAIB. L-Arginine (5 mM) partly inhibited the uptake in humans, but hardly affected that in rats. Betaine (10 mM) partly inhibited the uptake in rats, but hardly affected it in humans. These results suggest that SNAT1 is most likely the major contributor to system A-mediated MeAIB uptake by human and rat MVM vesicles and that the remaining uptake is mainly mediated by SNAT4 in humans and SNAT2 in rats. Thus, inhibition studies using betaine and L-arginine are useful to characterize the molecular mechanisms of system A-mediated transport.

Antibody uptake into neurons occurs primarily via clathrin-dependent Fcγ receptor endocytosis and is a prerequisite for acute tau protein clearance.

PubMed

Congdon, Erin E; Gu, Jiaping; Sait, Hameetha B R; Sigurdsson, Einar M

2013-12-06

Tau immunotherapy is effective in transgenic mice, but the mechanisms of Tau clearance are not well known. To this end, Tau antibody uptake was analyzed in brain slice cultures and primary neurons. Internalization was rapid (<1 h), saturable, and substantial compared with control mouse IgG. Furthermore, temperature reduction to 4 °C, an excess of unlabeled mouse IgG, or an excess of Tau antibodies reduced uptake in slices by 63, 41, and 62%, respectively (p = 0.002, 0.04, and 0.005). Uptake strongly correlated with total and insoluble Tau levels (r(2) = 0.77 and 0.87 and p = 0.002 and 0.0002), suggesting that Tau aggregates influence antibody internalization and/or retention within neurons. Inhibiting phagocytosis did not reduce uptake in slices or neuronal cultures, indicating limited microglial involvement. In contrast, clathrin-specific inhibitors reduced uptake in neurons (≤ 78%, p < 0.0001) and slices (≤ 35%, p = 0.03), demonstrating receptor-mediated endocytosis as the primary uptake pathway. Fluid phase endocytosis accounted for the remainder of antibody uptake in primary neurons, based on co-staining with internalized dextran. The receptor-mediated uptake is to a large extent via low affinity FcγII/III receptors and can be blocked in slices (43%, p = 0.04) and neurons (53%, p = 0.008) with an antibody against these receptors. Importantly, antibody internalization appears to be necessary for Tau reduction in primary neurons. Overall, these findings clarify that Tau antibody uptake is primarily receptor-mediated, that these antibodies are mainly found in neurons with Tau aggregates, and that their intracellular interaction leads to clearance of Tau pathology, all of which have major implications for therapeutic development of this approach.

Rapid transcapillary exchange and unidirectional neuronal uptake of noradrenaline in the perfused rabbit heart.

PubMed Central

Mann, G E; Yudilevich, D L

1984-01-01

Capillary permeability and cellular uptake of noradrenaline by the isolated artificially perfused rabbit heart was measured using rapid (less than 30 s) single-circulation tracer-dilution techniques. In a single coronary circulation capillary extractions of L-[14C]noradrenaline and D-[3H]mannitol (extracellular reference) relative to an intravascular marker, 125I-labelled albumin, were similar and above 60%. The 'apparent' volume of distribution for tracer noradrenaline was 2.5-fold larger than that measured for D-mannitol (0.32 ml g-1) suggesting cellular uptake of the amine. Unidirectional noradrenaline uptake was estimated by directly comparing coronary sinus dilution profiles of L-[3H]noradrenaline and D-[14C]mannitol. Michaelis-Menten saturation kinetics based on a single-entry system were determined (Km = 2.8 +/- 1.5 microM, Vmax = 2.1 +/- 0.5 nmol min-1 g-1, n = 4) by perfusing hearts with varying concentrations of L-noradrenaline (1-10 microM). Various known inhibitors of noradrenaline uptake were investigated to determine whether uptake was mediated by neuronal (uptake1) and/or extraneuronal (uptake2) mechanisms. Desipramine (5 microM), imipramine (5 microM) and metaraminol (2 microM) resulted in a 66-94% inhibition of noradrenaline influx. In comparison, the steroids, 17 beta-oestradiol (1 microM) and corticosterone (10 microM), and the noradrenaline metabolite normetanephrine (5 microM) caused virtually no inhibitory effects. The beta-adrenergic antagonist propranolol (5 microM) was also relatively ineffective. These results together with the kinetic constants estimated suggest that the rapid noradrenaline uptake reflects transport into adrenergic neurones lying in the coronary interstitium. The high resolution of this paired-tracer dilution technique has permitted a 'non-invasive' study of neuronal uptake mechanisms and its application may be of clinical value. PMID:6425496

Delivery Rate Affects Uptake of a Fluorescent Glucose Analog in Murine Metastatic Breast Cancer

PubMed Central

Rajaram, Narasimhan; Frees, Amy E.; Fontanella, Andrew N.; Zhong, Jim; Hansen, Katherine; Dewhirst, Mark W.; Ramanujam, Nirmala

2013-01-01

We demonstrate an optical strategy using intravital microscopy of dorsal skin flap window chamber models to image glucose uptake and vascular oxygenation in vivo. Glucose uptake was imaged using a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). SO2 was imaged using the differential absorption properties of oxygenated [HbO2] and deoxygenated hemoglobin [dHb]. This study was carried out on two sibling murine mammary adenocarcinoma lines, 4T1 and 4T07. 2-NBDG uptake in the 4T1 tumors was lowest when rates of delivery and clearance were lowest, indicating perfusion-limited uptake in poorly oxygenated tumor regions. For increasing rates of delivery that were still lower than the glucose consumption rate (as measured in vitro), both 2-NBDG uptake and the clearance rate from the tumor increased. When the rate of delivery of 2-NBDG exceeded the glucose consumption rate, 2-NBDG uptake decreased with any further increase in rate of delivery, but the clearance rate continued to increase. This inflection point was not observed in the 4T07 tumors due to an absence of low delivery rates close to the glucose consumption rate. In the 4T07 tumors, 2-NBDG uptake increased with increasing rates of delivery at low rates of clearance. Our results demonstrate that 2-NBDG uptake in tumors is influenced by the rates of delivery and clearance of the tracer. The rates of delivery and clearance are, in turn, dependent on vascular oxygenation of the tumors. Knowledge of the kinetics of tracer uptake as well as vascular oxygenation is essential to make an informed assessment of glucose demand of a tumor. PMID:24204635

Heart Rate and Oxygen Uptake Kinetics in Type 2 Diabetes Patients - A Pilot Study on the Influence of Cardiovascular Medication on Regulatory Processes.

PubMed

Koschate, Jessica; Drescher, Uwe; Baum, Klaus; Brinkmann, Christian; Schiffer, Thorsten; Latsch, Joachim; Brixius, Klara; Hoffmann, Uwe

2017-05-01

The aim of this pilot study was to investigate whether there are differences in heart rate and oxygen uptake kinetics in type 2 diabetes patients, considering their cardiovascular medication. It was hypothesized that cardiovascular medication would affect heart rate and oxygen uptake kinetics and that this could be detected using a standardized exercise test. 18 subjects were tested for maximal oxygen uptake. Kinetics were measured in a single test session with standardized, randomized moderate-intensity work rate changes. Time series analysis was used to estimate kinetics. Greater maxima in cross-correlation functions indicate faster kinetics. 6 patients did not take any cardiovascular medication, 6 subjects took peripherally acting medication and 6 patients were treated with centrally acting medication. Maximum oxygen uptake was not significantly different between groups. Significant main effects were identified regarding differences in muscular oxygen uptake kinetics and heart rate kinetics. Muscular oxygen uptake kinetics were significantly faster than heart rate kinetics in the group with no cardiovascular medication (maximum in cross-correlation function of muscular oxygen uptake vs. heart rate; 0.32±0.08 vs. 0.25±0.06; p=0.001) and in the group taking peripherally acting medication (0.34±0.05 vs. 0.28±0.05; p=0.009) but not in the patients taking centrally acting medication (0.28±0.05 vs. 0.30±0.07; n.s.). It can be concluded that regulatory processes for the achievement of a similar maximal oxygen uptake are different between the groups. The used standardized test provided plausible results for heart rate and oxygen uptake kinetics in a single measurement session in this patient group. © Georg Thieme Verlag KG Stuttgart · New York.

The significance of folic acid, tissue iron stores, and tissue viability in determining iron uptake from serum by thyroid tissue slices

PubMed Central

Buchanan, W. M.

1971-01-01

This paper describes an attempt to measure in vitro iron uptake from serum by human thyroid slices and to relate the uptake to tissue iron stores, folic acid status, and tissue viability. It is an extension of work previously reported (Buchanan, 1969). Thyroids were obtained from patients undergoing partial thyroidectomy for colloid goitre and serum from clinically normal healthy adults. The haemoglobin, serum iron, and folic acid levels of both thyroid and serum donors were measured and thyroids examined histologically for the presence of stainable iron. Viable and non-viable tissue slices were incubated in sera treated with radioactive iron so as to produce high and normal levels of transferrin saturation. Iron was taken up both from sera with normal and high transferrin saturation but the amount was, in almost all cases, greater from the more highly saturated. The uptake by non-viable tissue was appreciable but did not vary to any great extent from one serum to the next, and was attributed to simple diffusion of ionic iron into the tissue. There was, however, marked variation in uptake from different sera by viable tissue. It was concluded therefore that viability is a factor affecting the uptake. As the variation in uptake by viable tissue incubated in a single serum was significantly less than tissue incubated in a number of different sera it was further concluded that there was also a factor in the serum itself affecting iron uptake. The nature of the factor was not elucidated but neither folic acid nor levels of iron stores appeared to influence uptake because no correlation was found between iron uptake and iron stores or folic acid. Images PMID:5556118

The significance of alteration 2-[fluorine-18]fluoro-2-deoxy-(D)-glucose uptake in the liver and skeletal muscles of patients with hyperthyroidism.

PubMed

Chen, Yen-Kung; Chen, Yen-Ling; Tsui, Chih-Cheng; Wang, Su-Chen; Cheng, Ru-Hwa

2013-10-01

Hyperthyroidism leads to an enhanced demand for glucose. The hypothesis of the study is that 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) can demonstrate the alteration of systemic glucose metabolism in hyperthyroidism patients by measuring the FDG standard uptake value (SUV) in liver and skeletal muscle. Forty-eight active hyperthyroidism patients and 30 control participants were recruited for the study. The intensity of FDG uptake in the liver and thigh muscles was graded subjectively, comprising three groups: group I, higher FDG uptake in the liver; group II, equal FDG uptake in the liver and muscles; and group III, higher FDG uptake in the muscles. Ten subjects with FDG PET scans at hyperthyroid and euthyroid status were analyzed. Serum levels of thyroxine (T4) and triiodothyronine (T3) correlated to the SUVs of the liver and muscles. Forty-one patients (41/48, 85.4%) showed symmetrically increased FDG uptake in the muscles (22 in group I, 9 in group II, and 17 in group III). Group I patients were significantly older than group II (P = .02) and group III (P = .001) patients. The correlation coefficient between the serum T3, T4, and SUV levels in the muscles was significant (r = 0.47-0.77, P < .01), particularly in liver and muscle FDG uptake between hyperthyroid and euthyroid states. In the 30 control subjects, there was normal physiological FDG uptake in the liver and muscles. In PET scans showing a pattern of decreased liver and increased skeletal muscle FDG uptake in hyperthyroidism patients, this change of FDG distribution is correspondence to the severity of hyperthyroidism status. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Translocation of myocardial GLUT-4 and increased glucose uptake through activation of AMPK by AICAR.

PubMed

Russell, R R; Bergeron, R; Shulman, G I; Young, L H

1999-08-01

Insulin increases glucose uptake through the translocation of GLUT-4 via a pathway mediated by phosphatidylinositol 3-kinase (PI3K). In contrast, myocardial glucose uptake during ischemia and hypoxia is stimulated by the translocation of GLUT-4 to the surface of cardiac myocytes through a PI3K-independent pathway that has not been characterized. AMP-activated protein kinase (AMPK) activity is also increased by myocardial ischemia, and we examined whether AMPK stimulates glucose uptake and GLUT-4 translocation. In isolated rat ventricular papillary muscles, 5-aminoimidazole-4-carboxyamide-1-beta-D-ribofuranoside (AICAR), an activator of AMPK, as well as cyanide-induced chemical hypoxia and insulin, increased 2-[(3)H]deoxyglucose uptake two- to threefold. Wortmannin, a PI3K inhibitor, did not affect either the AICAR- or the cyanide-stimulated increase in deoxyglucose uptake but eliminated the insulin-stimulated increase in deoxyglucose uptake. Immunofluorescence studies demonstrated translocation of GLUT-4 to the myocyte sarcolemma in response to stimulation with AICAR, cyanide, or insulin. Preincubation of papillary muscles with the kinase inhibitor iodotubercidin or adenine 9-beta-D-arabinofuranoside (araA), a precursor of araATP (a competitive inhibitor of AMPK), decreased AICAR- and cyanide-stimulated glucose uptake but did not affect basal or insulin-stimulated glucose uptake. In vivo infusion of AICAR caused myocardial AMPK activation and GLUT-4 translocation in the rat. We conclude that AMPK activation increases cardiac muscle glucose uptake through translocation of GLUT-4 via a pathway that is independent of PI3K. These findings suggest that AMPK activation may be important in ischemia-induced translocation of GLUT-4 in the heart.

Altered spinal arachidonic acid turnover after peripheral nerve injury regulates regional glutamate concentration and neuropathic pain behaviors in rats.

PubMed

Sung, Backil; Wang, Shuxing; Zhou, Bei; Lim, Grewo; Yang, Liling; Zeng, Qing; Lim, Jeong-Ae; Wang, Jing Dong; Kang, Jing X; Mao, Jianren

2007-09-01

Spinal glutamate transporters (GT) have been implicated in the mechanisms of neuropathic pain; however, how spinal GT uptake activity is regulated remains unclear. Here we show that alteration of spinal arachidonic acid (AA) turnover after peripheral nerve injury regulated regional GT uptake activity and glutamate homeostasis. Chronic constriction nerve injury (CCI) in rats significantly reduced spinal GT uptake activity ((3)H-glutamate uptake) with an associated increase in extracellular AA and glutamate concentration from spinal microdialysates on postoperative day 8. AACOCF3 (a cytosolic phospholipase A2 inhibitor, 30mug) given intrathecally twice a day for postoperative day 1-7 reversed this CCI-induced spinal AA production, prevented the reduced spinal GT uptake activity and increased extracellular glutamate concentration. Conversely, alteration of spinal AA metabolism by diclofenac (a cyclooxygenase 1/2 inhibitor, 200mug) further reduced spinal GT uptake activity and increased extracellular glutamate concentration in CCI rats. GT uptake activity was also attenuated when AA (10 or 100nM) was directly added into spinal samples of naïve rats in an in vitro(3)H-glutamate uptake assay, indicating a direct inhibitory effect of AA on GT uptake activity. Consistent with these findings, AACOCF3 reduced the development of both thermal hyperalgesia and mechanical allodynia, whereas diclofenac exacerbated thermal hyperalgesia, in CCI rats. Thus, spinal AA turnover may serve as a regulator in CCI-induced changes in regional GT uptake activity, glutamate homeostasis, and neuropathic pain behaviors. These data suggest that regulating spinal AA turnover may be a useful approach to improving the clinical management of neuropathic pain.

Uptake of the antileishmania drug tafenoquine follows a sterol-dependent diffusion process in Leishmania.

PubMed

Manzano, José Ignacio; Carvalho, Luis; García-Hernández, Raquel; Poveda, José Antonio; Ferragut, José Antonio; Castanys, Santiago; Gamarro, Francisco

2011-11-01

The present study was designed to elucidate the mechanism of tafenoquine uptake in Leishmania and its sterol dependence. Because tafenoquine is a fluorescent compound, spectrofluorimetric analysis allowed us to monitor its uptake by Leishmania promastigotes and intracellular amastigotes, and to evaluate the effect of temperature, energy and H+ gradient on drug entry. The influence of sterols on tafenoquine uptake in Leishmania parasites was determined in experiments using sterol-depleting agents such as methyl-β-cyclodextrin or cholesterol oxidase. Tafenoquine exhibited fast entry kinetics into Leishmania in an energy-independent, but pH- and temperature-dependent, non-saturable process. Furthermore, sterol depletion decreased tafenoquine uptake. These findings suggest that Leishmania takes up tafenoquine by a diffusion process and that decreases in membrane sterol content may induce a decrease in drug uptake.

Sequential Actions of Rab5 and Rab7 Regulate Endocytosis in the Xenopus Oocyte

PubMed Central

Mukhopadhyay, Amitabha; Barbieri, Alejandro M.; Funato, Kouichi; Roberts, Richard; Stahl, Philip D.

1997-01-01

To explore the role of GTPases in endocytosis, we developed an assay using Xenopus oocytes injected with recombinant proteins to follow the uptake of the fluid phase marker HRP. HRP uptake was inhibited in cells injected with GTPγS or incubated with aluminum fluoride, suggesting a general role for GTPases in endocytosis. Injection of Rab5 into oocytes, as well as Rab5:Q79L, a mutant with decreased GTPase activity, increased HRP uptake. Injection of Rab5:S34N, the dominant-negative mutant, inhibited HRP uptake. Injection of N-ethylmaleimide–sensitive factor (NSF) stimulated HRP uptake, and ATPase-defective NSF mutants inhibited HRP uptake when coinjected with Rab5:Q79L, confirming a requirement for NSF in endocytosis. Surprisingly, injection of Rab7:WT stimulated both uptake and degradation/activation of HRP. The latter appears to be due to enhanced transport to a late endosomal/prelysosomal degradative compartment that is monensin sensitive. Enhancement of uptake by Rab7 appears to function via an Rab5-sensitive pathway in oocytes since the stimulatory effect of Rab7 was blocked by coinjection of Rab5:S34N. Stimulation of uptake by Rab5 was blocked by Rab5:S34N but not by Rab7:T22N. Our results suggest that Rab7, while functioning downstream of Rab5, may be rate limiting for endocytosis in oocytes. PMID:9087439

Cadmium uptake and xylem loading are active processes in the hyperaccumulator Sedum alfredii.

PubMed

Lu, Ling-li; Tian, Sheng-ke; Yang, Xiao-e; Li, Ting-qiang; He, Zhen-li

2009-04-01

Sedum alfredii is a well known cadmium (Cd) hyperaccumulator native to China; however, the mechanism behind its hyperaccumulation of Cd is not fully understood. Through several hydroponic experiments, characteristics of Cd uptake and translocation were investigated in the hyperaccumulating ecotype (HE) of S. alfredii in comparison with its non-hyperaccumulating ecotype (NHE). The results showed that at Cd level of 10 microM measured Cd uptake in HE was 3-4 times higher than the implied Cd uptake calculated from transpiration rate. Furthermore, inhibition of transpiration rate in the HE has no essential effect on Cd accumulation in shoots of the plants. Low temperature treatment (4 degrees C) significantly inhibited Cd uptake and reduced upward translocation of Cd to shoots for 9 times in HE plants, whereas no such effect was observed in NHE. Cadmium concentration was 3-4-fold higher in xylem sap of HE, as compared with that in external uptake solution, whereas opposite results were obtained for NHE. Cadmium concentration in xylem sap of HE was significantly reduced by the addition of metabolic inhibitors, carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP), in the uptake solutions, whereas no such effect was noted in NHE. These results suggest that Cd uptake and translocation is an active process in plants of HE S. alfredii, symplastic pathway rather than apoplastic bypass contributes greatly to root uptake, xylem loading and translocation of Cd to the shoots of HE, in comparison with the NHE plants.

Hot and Cool Spots of Primary Production, Respiration and 15N Nitrate and Ammonium Uptake: Spatial Heterogeneity in Tropical Streams and Rivers

NASA Astrophysics Data System (ADS)

Dodds, W. K.; Tromboni, F.; Neres-Lima, V.; Zandoná, E.; Moulton, T. P.

2016-12-01

While whole-stream measures of metabolism and uptake have become common methods to characterize biogeochemical transport and processing, less is known about how nitrogen (N) uptake, gross primary production (GPP) and ecosystem respiration (ER) covary among different stream substrata as smaller scales. We measured 15N ammonium and nitrate uptake seperately, and GPP and ER of ecosystem compartments (leaves, epilithon, sand-associated biota and macrophytes) in closed circulating chambers in three streams/ rivers of varied size. The streams drain pristine Brazilian Atlantic Rainforest watersheds and are all within a few km of eachother. The smallest stream had dense forest canopy cover; the largest river was almost completely open. GPP could not be detected in the closed canopy stream. Epilithon (biofilms on rocks) was a dominant compartment for GPP and N uptake in the two open streams, and macrophytes rivaled epilithon GPP and N uptake rates in the most open stream. Even though leaves covered only 1-3% of the stream bottom, they could account for around half of all the ER in the streams but almost no N uptake. Sand had minimal rates of N uptake, GPP and R associated with it in all streams due to relatively low organic material content. The data suggest that N uptake, GPP and ER of different substrata are not closely linked over relatively small spatial (dm) scales, and that different biogeochemical processes may map to different hot and cool spots for ecosystem rates.

[Increased glucose uptake by seborrheic keratosis on PET scan].

PubMed

Merklen-Djafri, C; Truntzer, P; Hassler, S; Cribier, B

2017-05-01

Positron emission tomography (PET) is an examination based upon the uptake of a radioactive tracer by hypermetabolic cells. It is primarily used in tandem with tomodensitometry (PET-TDM) for cancer staging because of its high sensitivity and specificity for the detection of metastases. However, unusually high uptake may occur with benign tumours, including skin tumours. Herein, we report an extremely rare case of pathological uptake levels resulting from seborrhoeic keratosis. A 55-year-old male patient with oesophageal squamous-cell carcinoma was referred to us following the discovery of an area of high marker uptake following PET-TDM and corresponding to a pigmented skin lesion. No other areas of suspect high uptake were seen. The lesion was surgically excised and histological examination indicated seborrhoeic keratosis. The histological appearance was that of standard seborrhoeic keratosis without any notable mitotic activity. PET-TDM is an examination that enables diagnosis of malignancy. However, rare cases have been described of increased marker uptake by benign cutaneous tumours such as histiocytofibroma, pilomatricoma and condyloma. To date, there have only been only very few cases of increased uptake due to seborrhoeic keratosis. This extremely unusual case of increased glucose uptake in PET-TDM due to seborrhoeic keratosis confirms that the hypermetabolic activity detected by this examination is not necessarily synonymous with malignancy and that confirmation by clinical and histological findings is essential. The reasons for increased metabolic activity within such benign tumours are not known. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Pulmonary vascular clearance of harmful endogenous macromolecules in a porcine model of acute liver failure.

PubMed

Nedredal, Geir I; Elvevold, Kjetil; Chedid, Marcio F; Ytrebø, Lars M; Rose, Christopher F; Sen, Sambit; Smedsrød, Bård; Jalan, Rajiv; Revhaug, Arthur

2016-01-01

Pulmonary complications are common in acute liver failure (ALF). The role of the lungs in the uptake of harmful soluble endogenous macromolecules was evaluated in a porcine model of ALF induced by hepatic devascularization (n = 8) vs. controls (n = 8). In additional experiments, pulmonary uptake was investigated in healthy pigs. Fluorochrome-labeled modified albumin (MA) was applied to investigate the cellular uptake. As compared to controls, the ALF group displayed a 4-fold net increased lung uptake of hyaluronan, and 5-fold net increased uptake of both tissue plasminogen activator and lysosomal enzymes. Anatomical distribution experiments in healthy animals revealed that radiolabeled MA uptake (taken up by the same receptor as hyaluronan) was 53% by the liver, and 24% by the lungs. The lung uptake of LPS was 14% whereas 60% remained in the blood. Both fluorescence and electron microscopy revealed initial uptake of MA by pulmonary endothelial cells (PECs) with later translocation to pulmonary intravascular macrophages (PIMs). Moreover, the presence of PIMs was evident 10 min after injection. Systemic inflammatory markers such as leukopenia and increased serum TNF-α levels were evident after 20 min in the MA and LPS groups. Significant lung uptake of harmful soluble macromolecules compensated for the defect liver scavenger function in the ALF-group. Infusion of MA induced increased TNF-α serum levels and leukopenia, similar to the effect of the known inflammatory mediator LPS. These observations suggest a potential mechanism that may contribute to lung damage secondary to liver disease.

CHL1 is a dual-affinity nitrate transporter of Arabidopsis involved in multiple phases of nitrate uptake.

PubMed Central

Liu, K H; Huang, C Y; Tsay, Y F

1999-01-01

Higher plants have both high- and low-affinity nitrate uptake systems. These systems are generally thought to be genetically distinct. Here, we demonstrate that a well-known low-affinity nitrate uptake mutant of Arabidopsis, chl1, is also defective in high-affinity nitrate uptake. Two to 3 hr after nitrate induction, uptake activities of various chl1 mutants at 250 microM nitrate (a high-affinity concentration) were only 18 to 30% of those of wild-type plants. In these mutants, both the inducible phase and the constitutive phase of high-affinity nitrate uptake activities were reduced, with the inducible phase being severely reduced. Expressing a CHL1 cDNA driven by the cauliflower mosaic virus 35S promoter in a transgenic chl1 plant effectively recovered the defect in high-affinity uptake for the constitutive phase but not for the induced phase, which is consistent with the constitutive level of CHL1 expression in the transgenic plant. Kinetic analysis of nitrate uptake by CHL1-injected Xenopus oocytes displayed a biphasic pattern with a Michaelis-Menten Km value of approximately 50 microM for the high-affinity phase and approximately 4 mM for the low-affinity phase. These results indicate that in addition to being a low-affinity nitrate transporter, as previously recognized, CHL1 is also involved in both the inducible and constitutive phases of high-affinity nitrate uptake in Arabidopsis. PMID:10330471

Toxicokinetics/toxicodynamics links bioavailability for assessing arsenic uptake and toxicity in three aquaculture species.

PubMed

Chen, Wei-Yu; Liao, Chung-Min

2012-11-01

The purpose of this study was to link toxicokinetics/toxicodynamics (TK/TD) and bioavailability-based metal uptake kinetics to assess arsenic (As) uptake and bioaccumulation in three common farmed species of tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), and freshwater clam (Corbicula fluminea). We developed a mechanistic framework by linking damage assessment model (DAM) and bioavailability-based Michaelis-Menten model for describing TK/TD and As uptake mechanisms. The proposed model was verified with published acute toxicity data. The estimated TK/TD parameters were used to simulate the relationship between bioavailable As uptake and susceptibility probability. The As toxicity was also evaluated based on a constructed elimination-recovery scheme. Absorption rate constants were estimated to be 0.025, 0.016, and 0.175 mL g(-1) h(-1) and As uptake rate constant estimates were 22.875, 63.125, and 788.318 ng g(-1) h(-1) for tilapia, milkfish, and freshwater clam, respectively. Here we showed that a potential trade-off between capacities of As elimination and damage recovery was found among three farmed species. Moreover, the susceptibility probability can also be estimated by the elimination-recovery relations. This study suggested that bioavailability-based uptake kinetics and TK/TD-based DAM could be integrated for assessing metal uptake and toxicity in aquatic organisms. This study is useful to quantitatively assess the complex environmental behavior of metal uptake and implicate to risk assessment of metals in aquaculture systems.

Alleviation of proton toxicity by nitrate uptake specifically depends on nitrate transporter 1.1 in Arabidopsis.

PubMed

Fang, Xian Zhi; Tian, Wen Hao; Liu, Xing Xing; Lin, Xian Yong; Jin, Chong Wei; Zheng, Shao Jian

2016-07-01

Protons in acid soil are highly rhizotoxic to plants, but the mechanism of tolerance of plants to protons is largely unknown. Nitrate uptake by root cells is accompanied by the uptake of protons. Therefore, nitrate uptake transporters (NRTs) may be involved in plant tolerance to proton toxicity. We investigated the root nitrate uptake response to proton stress in Arabidopsis and its association with proton tolerance using NRT-related mutants and pharmacological methods. Lack of NRT1.1 in knockout nrt1.1 mutants led to impaired proton tolerance in nitrate-sufficient growth medium, whereas no difference was seen between wild-type plants and NRT1.2-, NRT2.1-, NRT2.2-, and NRT2.4-null mutants. Another nrt1.1 point mutant, which is defective in nitrate uptake but has a normal nitrate-sensing function, also had impaired proton tolerance compared with the wild-type plant. Furthermore, proton stress induced NRT1.1-mediated nitrate uptake. These results indicate that NRT1.1-conferred proton tolerance depends on nitrate uptake activity. In addition, the rooting medium was alkalified by wild-type plants, but not by knockout nrt1.1 mutants, and in pH-buffered medium, there were no differences in proton tolerance between wild-type plants and knockout nrt1.1 mutants. We conclude that NRT1.1-mediated nitrate uptake plays a crucial role in plant proton tolerance by alkalifying the rhizosphere. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Measuring the serotonin uptake site using (/sup 3/H)paroxetine--a new serotonin uptake inhibitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gleiter, C.H.; Nutt, D.J.

1988-01-01

Serotonin is an important neurotransmitter that may be involved in ethanol preference and dependence. It is possible to label the serotonin uptake site in brain using the tricyclic antidepressant imipramine, but this also binds to other sites. We have used the new high-affinity uptake blocker paroxetine to define binding to this site and report it to have advantages over imipramine as a ligand.

Leaf and Stem CO2 Uptake in the Three Subfamilies of the Cactaceae 1

PubMed Central

Nobel, Park S.; Hartsock, Terry L.

1986-01-01

Net CO2 uptake over 24-hour periods was examined for the leaves and for the stems of 11 species of cacti representing all three subfamilies. For Pereskia aculeata, Pereskia grandifolia, and Maihuenia poeppigii (subfamily Pereskioideae), all the net shoot CO2 uptake was by the leaves and during the daytime. In contrast, for the leafless species Carnegiea gigantea, Ferocactus acanthodes, Coryphantha vivipara, and Mammillaria dioica (subfamily Cactoideae), all the shoot net CO2 uptake was by the stems and at night. Similarly, for leafless Opuntia ficus-indica (subfamily Opuntioideae), all net CO2 uptake occurred at night. For leafy members of the Opuntioideae (Pereskiopsis porteri, Quiabentia chacoensis, Austrocylindropuntia subulata), at least 88% of the shoot CO2 uptake over 24 hours was by the leaves and some CO2 uptake occurred at night. Leaves responded to the instantaneous level of photosynthetically active radiation (PAR) during the daytime, as occurs for C3 plants, whereas nocturnal CO2 uptake by stems of O. ficus-indica and F. acanthodes responded to the total daily PAR, as occurs for Crassulacean acid metabolism (CAM) plants. Thus, under the well-watered conditions employed, the Pereskioideae behaved as C3 plants, the Cactoideae behaved as CAM plants, and the Opuntioideae exhibited characteristics of both pathways. PMID:16664741

Amperozide, a putative anti-psychotic drug: Uptake inhibition and release of dopamine in vitro in the rat brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eriksson, E.

1990-01-01

The effects of amperozide (a diphenylbutylpiperazinecarboxamide derivative) on the uptake and release of {sup 3}H-dopamine in vitro were investigated. Amperozide inhibited the amphetamine-stimulated release of dopamine from perfused rat striatal tissue in a dose-dependent manner. With 1 and 10 {mu}m amperozide there was significant inhibition of the amphetamine-stimulated release of dopamine, to 44 and 36 % of control. In contrast, 10 {mu}M amperozide significantly strengthened the electrically stimulated release of dopamine from perfused striatal slices. Amperozide 1-10 {mu}M had no significant effect on the potassium-stimulated release of dopamine, 10 {mu}M amperozide also slightly increased the basal release of {sup 3}H-dopaminemore » from perfused striatal tissue. These effects on various types of release are similar to those reported for uptake inhibitors. The uptake of dopamine in striatal tissue was inhibited by amperozide with IC{sub 50} values of 18 {mu}M for uptake in chopped tissue and 1.0 {mu}M for uptake in synaptosomes. Amperozide also inhibited the uptake of serotonin in synaptosomes from frontal cortex, IC{sub 50} = 0.32 {mu}M and the uptake of noradrenaline in cortical synaptosomes, IC{sub 50} = 0.78 {mu}M.« less

Reactive Uptake of Dimethylamine by Ammonium Sulfate and Ammonium Sulfate-Sucrose Mixed Particles.

PubMed

Chu, Yangxi; Chan, Chak K

2017-01-12

Short-chain alkyl amines can undergo gas-to-particle partitioning via reactive uptake by ammonium salts, whose phases have been thought to largely influence the extent of amine uptake. Previous studies mainly focused on particles of single ammonium salt at either dry or wet conditions without any addition of organic compounds. Here we report the uptake of dimethylamine (DMA) by ammonium sulfate (AS) and AS-sucrose mixed particles at different relative humidities (RHs) using an electrodynamic balance coupled with in situ Raman spectroscopy. DMA is selected as a representative of short-chain alkyl amines, and sucrose is used as a surrogate of viscous and hydrophilic organics. Effective DMA uptake was observed for most cases, except for the water-limiting scenario at <5% RH and the formation of an ultraviscous sucrose coating at 10% RH and below. DMA uptake coefficients (γ) were estimated using the particle mass measurements during DMA uptake. Addition of sucrose can increase γ by absorbing water or inhibiting AS crystallization and decrease γ by elevating the particle viscosity and forming a coating layer. DMA uptake can be facilitated for crystalline AS or retarded for aqueous AS with hydrophilic viscous organics (e.g., secondary organic material formed via the oxidation of biogenic volatile organic compounds) present in aerosol particles.

Effect of Tumor Microenvironment on Selective Uptake of Boric Acid in HepG2 Human Hepatoma Cells.

PubMed

Bai, Yu-Chi; Hsia, Yu-Chun; Lin, Yu-Ting; Chen, Kuan-Hao; Chou, Fong-In; Yang, Chia-Min; Chuang, Yung-Jen

2017-11-01

Feasibility and efficacy of boric acid (BA)-mediated boron neutron capture therapy (BNCT) was first demonstrated by eliminating hepatocellular carcinoma (HCC) in a rat model. Furthermore, selective uptake of BA by liver tumor cells was shown in a rabbit model. To gain further insight, this study aimed to investigate the mechanisms of transportation and selective uptake of BA in HepG2 liver tumor cells. Transportation of BA in HepG2 cells was analyzed by time-course assays and by analyzing the rate of diffusion versus the concentration of BA. The effect of different tumor conditions on BA uptake was studied by treating HepG2 cells with 25 μg 10 B/ml BA under different concentrations of glucose, at different pH and in the presence of water-soluble cholesterol. HepG2 cells mainly uptake BA by simple diffusion. Cell membrane permeability may also contribute to tumor-specific uptake of BA. The selective uptake of BA was achieved primarily by diffusion, while other factors, such as low pH and increased membrane fluidity, which are hallmarks of HCC, might further enhance BA uptake. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Written pretest information and germline BRCA1/2 pathogenic variant testing in unselected breast cancer patients: predictors of testing uptake.

PubMed

Nilsson, Martin P; Nilsson, Erik D; Silfverberg, Barbro; Borg, Åke; Loman, Niklas

2018-06-06

This study aimed to evaluate predictors of testing uptake among unselected breast cancer patients who were offered germline BRCA1/2 testing in a prospective study. Pretest information was provided by a standardized invitation letter instead of in-person counseling. Data was abstracted from medical records. Using multivariate logistic regressions, predictors of testing uptake were analyzed. The overall uptake of testing was 67% (539 of 805 patients). Low uptake rates were found for patients aged ≥80 years (33%), and patients born outside of Europe (37%). In adjusted analysis, age ≥80 years (odds ratio [OR] 0.10; P = 0.002), psychiatric disorders (OR 0.46; P = 0.006), occupation requiring at least 3 years of university or college education (OR 2.03; P = 0.003), and breast cancer or ovarian cancer in first-degree or second-degree relatives (OR 1.66; P = 0.02) were independently associated with uptake of BRCA1/2 testing. Somatic comorbidity in patients aged <70 years was associated with lower testing uptake. Testing uptake varies across different subgroups according to patient-related factors that are readily available in the medical records. Knowledge about these factors enables health care professionals to identify patients who are less likely to pursue genetic testing.

A five-year study of the impact of nitrogen addition on methane uptake in alpine grassland.

PubMed

Yue, Ping; Li, Kaihui; Gong, Yanming; Hu, Yukun; Mohammat, Anwar; Christie, Peter; Liu, Xuejun

2016-08-30

It remains unclear how nitrogen (N) deposition affects soil methane (CH4) uptake in semiarid and arid zones. An in situ field experiment was conducted from 2010 to 2014 to systematically study the effect of various N application rates (0, 10, 30, and 90 kg N ha(-1) yr(-1)) on CH4 flux in alpine grassland in the Tianshan Mountains. No significant influence of N addition on CH4 uptake was found. Initially the CH4 uptake rate increased with increasing N application rate by up to 11.5% in 2011 and then there was gradual inhibition by 2014. However, the between-year variability in CH4 uptake was very highly significant with average uptake ranging from 52.9 to 106.6 μg C m(-2) h(-1) and the rate depended largely on seasonal variability in precipitation and temperature. CH4 uptake was positively correlated with soil temperature, air temperature and to a lesser extent with precipitation, and was negatively correlated with soil moisture and NO3(-)-N content. The results indicate that between-year variability in CH4 uptake was impacted by precipitation and temperature and was not sensitive to elevated N deposition in alpine grassland.

Altered carnitine transport in pressure-overload hypertrophied rat hearts

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Rourke, B.; Foster, K.; Reibel, D.K.

1986-03-01

The authors have previously observed reduced carnitine levels in hypertrophied hearts of rats subjected to aortic constriction. In an attempt to determine the mechanism for reduced myocardial carnitine content, carnitine transport was examined in isolated perfused hearts. Hearts were excised from sham-operated and aortic-constricted rats 3 weeks following surgery and perfused at 60 mm Hg aortic pressure with buffer containing various concentrations of L-/sup 14/C-carnitine. Carnitine uptake by control and hypertrophied hearts was linear throughout 30 minutes of perfusion with 40 ..mu..M carnitine. Total carnitine uptake was significantly reduced by 25% in hypertrophied hearts at each time point examined. Themore » reduction in uptake by hypertrophied hearts was also evident when hearts were perfused with 100 or 200 ..mu..M carnitine. When 0.05 mM mersalyl acid was included in the buffer to inhibit the carrier-mediated component of transport, no difference in carnitine uptake was observed indicating that the transport of carnitine by diffusion was unaltered in the hypertrophied myocardium. Carrier-mediated carnitine uptake (total uptake - uptake by diffusion) was significantly reduced by approximately 40% in hypertrophied hearts at all concentrations examined. Thus, the reduction in carnitine content in the pressure-overload hypertrophied rat heart appears to be due to a reduction in carrier-mediated carnitine uptake by the heart.« less

A five-year study of the impact of nitrogen addition on methane uptake in alpine grassland

PubMed Central

Yue, Ping; Li, Kaihui; Gong, Yanming; Hu, Yukun; Mohammat, Anwar; Christie, Peter; Liu, Xuejun

2016-01-01

It remains unclear how nitrogen (N) deposition affects soil methane (CH4) uptake in semiarid and arid zones. An in situ field experiment was conducted from 2010 to 2014 to systematically study the effect of various N application rates (0, 10, 30, and 90 kg N ha−1 yr−1) on CH4 flux in alpine grassland in the Tianshan Mountains. No significant influence of N addition on CH4 uptake was found. Initially the CH4 uptake rate increased with increasing N application rate by up to 11.5% in 2011 and then there was gradual inhibition by 2014. However, the between-year variability in CH4 uptake was very highly significant with average uptake ranging from 52.9 to 106.6 μg C m−2 h−1 and the rate depended largely on seasonal variability in precipitation and temperature. CH4 uptake was positively correlated with soil temperature, air temperature and to a lesser extent with precipitation, and was negatively correlated with soil moisture and NO3−-N content. The results indicate that between-year variability in CH4 uptake was impacted by precipitation and temperature and was not sensitive to elevated N deposition in alpine grassland. PMID:27571892

Contextual factors associated with uptake of breast and cervical cancer screening: A systematic review of the literature.

PubMed

Plourde, Natasha; Brown, Hilary K; Vigod, Simone; Cobigo, Virginie

2016-01-01

Existing research on barriers to breast and cervical cancer screening uptake has focused primarily on socio-demographic characteristics of individuals. However, contextual factors, such as service organization, as well as healthcare providers' training and practices, are more feasibly altered to increase health service use. The objective of the authors in this study was to perform a critical systematic review of the literature to identify contextual factors at the provider- and system-level that were associated with breast and cervical cancer screening uptake. Studies published from 2000 to 2013 were identified through PubMed and PsycInfo. Methodologic quality was assessed, and studies were examined for themes related to provider- and system-level factors associated with screening uptake. Thirteen studies met the inclusion criteria. Findings revealed a positive association between patients' receipt of provider recommendation and uptake of breast and cervical cancer screening. Uptake was also higher among patients of female providers. Facilities with flexible appointment times and reminders had higher mammography and Pap test uptake. Similarly, greater organizational commitment to quality and performance had higher breast and cervical cancer screening rates. Knowledge provided in this review could be used in future research to inform the development of public health policy and clinical programs to improve screening uptake.

Schools That Make a Difference to Post-Compulsory Uptake of Physical Science Subjects: Some comparative case studies in England

NASA Astrophysics Data System (ADS)

Bennett, Judith; Lubben, Fred; Hampden-Thompson, Gillian

2013-03-01

This paper presents the findings of the qualitative component of a combined methods research study that explores a range of individual and school factors that influence the uptake of chemistry and physics in post-compulsory study in England. The first phase involves using the National Pupil Database to provide a sampling frame to identify four matched pairs of high-uptake and low-uptake schools by salient school factors. Case studies of these eight schools indicate that students employ selection strategies related to their career aspirations, their sense of identity and tactics, and their prior experience. The school factors influencing subject choice relate to school management, student support and guidance, and student empowerment. The most notable differences between students in high-uptake and low-uptake schools are that students in high-uptake schools appear to make a proactive choice in relation to career aspirations, rather than a reactive choice on the basis of past experience. Schools with a high uptake offer a diverse science curriculum in the final two years of compulsory study, set higher examination entry requirements for further study and, crucially, provide a range of opportunities for students to interact with the world of work and to gain knowledge and experience of science-related careers.

Macrophages phagocytose nonopsonized silica particles using a unique microtubule-dependent pathway

PubMed Central

Gilberti, Renée M.; Knecht, David A.

2015-01-01

Silica inhalation leads to the development of the chronic lung disease silicosis. Macrophages are killed by uptake of nonopsonized silica particles, and this is believed to play a critical role in the etiology of silicosis. However, the mechanism of nonopsonized-particle uptake is not well understood. We compared the molecular events associated with nonopsonized- and opsonized-particle phagocytosis. Both Rac and RhoA GTPases are activated upon nonopsonized-particle exposure, whereas opsonized particles activate either Rac or RhoA. All types of particles quickly generate a PI(3,4,5)P3 and F-actin response at the particle attachment site. After formation of a phagosome, the events related to endolysosome-to-phagosome fusion do not significantly differ between the pathways. Inhibitors of tyrosine kinases, actin polymerization, and the phosphatidylinositol cascade prevent opsonized- and nonopsonized-particle uptake similarly. Inhibition of silica particle uptake prevents silica-induced cell death. Microtubule depolymerization abolished uptake of complement-opsonized and nonopsonized particles but not Ab-opsonized particles. Of interest, regrowth of microtubules allowed uptake of new nonopsonized particles but not ones bound to cells in the absence of microtubules. Although complement-mediated uptake requires macrophages to be PMA-primed, untreated cells phagocytose nonopsonized silica and latex. Thus it appears that nonopsonized-particle uptake is accomplished by a pathway with unique characteristics. PMID:25428990

Factors Influencing Uptake of Sylvatic Plague Vaccine Baits by Prairie Dogs.

PubMed

Abbott, Rachel C; Russell, Robin E; Richgels, Katherine L D; Tripp, Daniel W; Matchett, Marc R; Biggins, Dean E; Rocke, Tonie E

2017-11-20

Sylvatic plague vaccine (SPV) is a virally vectored bait-delivered vaccine expressing Yersinia pestis antigens that can protect prairie dogs (Cynomys spp.) from plague and has potential utility as a management tool. In a large-scale 3-year field trial, SPV-laden baits containing the biomarker rhodamine B (used to determine bait consumption) were distributed annually at a rate of approximately 100-125 baits/hectare along transects at 58 plots encompassing the geographic ranges of four species of prairie dogs. We assessed site- and individual-level factors related to bait uptake in prairie dogs to determine which were associated with bait uptake rates. Overall bait uptake for 7820 prairie dogs sampled was 70% (95% C.I. 69.9-72.0). Factors influencing bait uptake rates by prairie dogs varied by species, however, in general, heavier animals had greater bait uptake rates. Vegetation quality and day of baiting influenced this relationship for black-tailed, Gunnison's, and Utah prairie dogs. For these species, baiting later in the season, when normalized difference vegetation indices (a measure of green vegetation density) are lower, improves bait uptake by smaller animals. Consideration of these factors can aid in the development of species-specific SPV baiting strategies that maximize bait uptake and subsequent immunization of prairie dogs against plague.

Factors influencing uptake of sylvatic plague vaccine baits by prairie dogs

USGS Publications Warehouse

Abbott, Rachel C.; Russell, Robin E.; Richgels, Katherine; Tripp, Daniel W.; Matchett, Marc R.; Biggins, Dean E.; Rocke, Tonie E.

2017-01-01

Sylvatic plague vaccine (SPV) is a virally vectored bait-delivered vaccine expressing Yersinia pestis antigens that can protect prairie dogs (Cynomys spp.) from plague and has potential utility as a management tool. In a large-scale 3-year field trial, SPV-laden baits containing the biomarker rhodamine B (used to determine bait consumption) were distributed annually at a rate of approximately 100–125 baits/hectare along transects at 58 plots encompassing the geographic ranges of four species of prairie dogs. We assessed site- and individual-level factors related to bait uptake in prairie dogs to determine which were associated with bait uptake rates. Overall bait uptake for 7820 prairie dogs sampled was 70% (95% C.I. 69.9–72.0). Factors influencing bait uptake rates by prairie dogs varied by species, however, in general, heavier animals had greater bait uptake rates. Vegetation quality and day of baiting influenced this relationship for black-tailed, Gunnison’s, and Utah prairie dogs. For these species, baiting later in the season, when normalized difference vegetation indices (a measure of green vegetation density) are lower, improves bait uptake by smaller animals. Consideration of these factors can aid in the development of species-specific SPV baiting strategies that maximize bait uptake and subsequent immunization of prairie dogs against plague.

Sternal uptake of 99mTc-MAA in thoracic outlet syndrome.

PubMed

Matsusaka, Yohji; Nakahara, Tadaki; Iwabuchi, Yu; Kameyama, Masashi; Murakami, Koji

2015-12-01

Tc-macroaggregated albumin (MAA) uptake in the vertebrae has been reported in central vein occlusion, although its sternal uptake is rarely seen. We present a case in which Tc-MAA SPECT/CT showed spotty uptake in the sternum. Contrast-enhanced CT revealed marked narrowing of the left subclavian vein at the thoracic outlet with a developed collateral vein running, in the left anterior chest subcutaneous tissue, between the sternum and left axilla. In this case, IV injection of Tc-MAA from the left forearm probably led to bone marrow uptake in the sternum due to retrograde venous flow through the collateral vein.

Pulmonary uptake in Indium-111 leukocyte imaging: clinical significance in patients with suspected occult infections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, P.S.; Datz, F.L.; Disbro, M.A.

1984-02-01

A retrospective review was undertaken to evaluate the frequency and significance of pulmonary activity noted on 306 indium-111 leukocyte studies involving 232 patients with suspected occult infections. Forty-eight studies showed pulmonary activity in one of two patterns of uptake, focal or diffuse. Fourteen of 27 studies (52%) with focal uptake and two of 21 studies (10%) with diffuse uptake were associated with infectious processes. Lung uptake of indium-111-labeled leukocytes was a poor predictor of pulmonary infection in patients studied for occult infection, although the focal pattern was more likely than the diffuse pattern to be associated with infection.

Recovery of Platinum from Dilute Chloride Media Using Biosorbents

NASA Astrophysics Data System (ADS)

Zeytuncu, B.; Morcali, M. H.; Yucel, O.

Pistachio nut shells and Rice husk, a biomass residue, were investigated as adsorbents for the platinum uptake from synthetically prepared dilute chloroplatinic acid solutions. The effects of the different uptake parameters on platinum uptake (%) were studied in detail on a batch sorption. Before the pistachio nut shell material was activated, platinum uptake (%) was poor compared with rice husk. However, after the pistachio nut shell material was activated at 1000°C under an argon atmosphere, the platinum uptake (%) increased two-fold. The pistachio nut shell (inactivated and activated) and rice husk were characterized by Attenuated Total Reflection-Fourier transform infrared spectroscopy (ATR-FTIR).

Separation of solute and particulate vectors of heavy metal uptake in controlled suspension-feeding experiments with Macoma balthica

USGS Publications Warehouse

Harvey, R.W.; Luoma, S.N.

1985-01-01

Radioisotope labelling experiments with the estuarine clam, Macoma balthica, are described, in which a filter chamber device was used to separate solute metal uptake from uptake, of metals associated with suspended bacteria. Solute uptake contributed a majority of the 14-day total body burdens of 65Zn and 109Cd, whereas 57Co uptake largely resulted from ingestion of isotope-laden bacteria. In contrast to those for 109Cd and 65Zn, 57Co tissue distributions at 3 weeks differed significantly (p < 0.05) between feeding and non-feeding clams (housed within filter chambers). ?? 1985 Dr W. Junk Publishers.

Uptake of different species of iodine by water spinach and its effect to growth.

PubMed

Weng, Huan-Xin; Yan, Ai-Lan; Hong, Chun-Lai; Xie, Lin-Li; Qin, Ya-Chao; Cheng, Charles Q

2008-08-01

A hydroponic experiment has been carried out to study the influence of iodine species [iodide (I(-)), iodate (IO(-)(3)), and iodoacetic acid (CH(2)ICOO(-))] and concentrations on iodine uptake by water spinach. Results show that low levels of iodine in the nutrient solution can effectively stimulate the growth of biomass of water spinach. When iodine levels in the nutrient solution are from 0 to 1.0 mg/l, increases in iodine levels can linearly augment iodine uptake rate by the leafy vegetables from all three species of iodine, and the uptake effects are in the following order: CH(2)ICOO(-) >I(-)>IO(-)(3). In addition, linear correlation was observed between iodine content in the roots and shoots of water spinach, and their proportion is 1:1. By uptake of I(-), vitamin C (Vit C) content in water spinach increased, whereas uptake of IO(-)(3) and CH(2)ICOO(-) decreased water spinach Vit C content. Furthermore, through uptake of I(-) and IO(-)(3). The nitrate content in water spinach was increased by different degrees.

Lung damage and pulmonary uptake of serotonin in intact dogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dawson, C.A.; Christensen, C.W.; Rickaby, D.A.

1985-06-01

The authors examined the influence of glass bead embolization and oleic acid, dextran, and imipramine infusion on the pulmonary uptake of trace doses of (/sup 3/H)serotonin and the extravascular volume accessible to (/sup 14/C)antipyrine in anesthetized dogs. Embolization and imipramine decreased serotonin uptake by 53 and 61%, respectively, but no change was observed with oleic acid or dextran infusion. The extravascular volume accessible to the antipyrine was reduced by 77% after embolization and increased by 177 and approximately 44% after oleic acid and dextran infusion, respectively. The results suggest that when the perfused endothelial surface is sufficiently reduced, as withmore » embolization, the uptake of trace doses of serotonin will be depressed. In addition, decreases in serotonin uptake in response to imipramine in this study and in response to certain endothelial toxins in other studies suggest that serotonin uptake can reveal certain kinds of changes in endothelial function. However, the lack of a response to oleic acid-induced damage in the present study suggests that serotonin uptake is not sensitive to all forms of endothelial damage.« less

Diselenolane-mediated cellular uptake.

PubMed

Chuard, Nicolas; Poblador-Bahamonde, Amalia I; Zong, Lili; Bartolami, Eline; Hildebrandt, Jana; Weigand, Wolfgang; Sakai, Naomi; Matile, Stefan

2018-02-21

The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.

Cyclic variations in nitrogen uptake rate of soybean plants: ammonium as a nitrogen source

NASA Technical Reports Server (NTRS)

Henry, L. T.; Raper, C. D. Jr

1989-01-01

When NO3- is the sole nitrogen source in flowing solution culture, the net rate of nitrogen uptake by nonnodulated soybean (Glycine max L. Merr. cv Ransom) plants cycles between maxima and minima with a periodicity of oscillation that corresponds with the interval of leaf emergence. Since soybean plants accumulate similar quantities of nitrogen when either NH4+ or NO3- is the sole source in solution culture controlled at pH 6.0, an experiment was conducted to determine if the oscillations in net rate of nitrogen uptake also occur when NH4+ is the nitrogen source. During a 21-day period of vegetative development, net uptake of NH4+ was measured daily by ion chromatography as depletion of NH4+ from a replenished nutrient solution containing 1.0 millimolar NH4+. The net rate of NH4+ uptake oscillated with a periodicity that was similar to the interval of leaf emergence. Instances of negative net rates of uptake indicate that the transition between maxima and minima involved changes in influx and efflux components of net NH4+ uptake.

Uptake of pharmaceuticals by plants grown under hydroponic conditions and natural occurring plant species: A review.

PubMed

Madikizela, Lawrence Mzukisi; Ncube, Somandla; Chimuka, Luke

2018-04-27

Sizeable amount of research has been conducted on the possible uptake of pharmaceuticals by plants from contaminated soil and water used for irrigation of crops. In most cases, pharmaceuticals are taken by roots and translocated into various tissues by transpiration and diffusion. Due to the plant uptake, the occurrence of pharmaceuticals in food sources such as vegetables is a public concern. Few review papers focusing on the uptake of pharmaceuticals, in particular antibiotics, and their translocation in plant tissues have been published. In the current review paper, the work conducted on the uptake of pharmaceuticals belonging to different therapeutic groups such as antibiotics, non-steroidal anti-inflammatory drugs, β-blockers and antiepileptics is reviewed. Such work includes the occurrence of pharmaceuticals in plants, translocation once taken by plants, toxicity studies as well as implications and future studies. Furthermore, the advantages and drawbacks associated with the detection and uptake of these pharmaceuticals by plants are discussed. In addition, the physico-chemical properties that could influence the plant uptake of pharmaceuticals are deliberated. Copyright © 2018 Elsevier B.V. All rights reserved.

Modeling the relationship between fluorodeoxyglucose uptake and tumor radioresistance as a function of the tumor microenvironment.

PubMed

Jeong, Jeho; Deasy, Joseph O

2014-01-01

High fluorodeoxyglucose positron emission tomography (FDG-PET) uptake in tumors has often been correlated with increasing local failure and shorter overall survival, but the radiobiological mechanisms of this uptake are unclear. We explore the relationship between FDG-PET uptake and tumor radioresistance using a mechanistic model that considers cellular status as a function of microenvironmental conditions, including proliferating cells with access to oxygen and glucose, metabolically active cells with access to glucose but not oxygen, and severely hypoxic cells that are starving. However, it is unclear what the precise uptake levels of glucose should be for cells that receive oxygen and glucose versus cells that only receive glucose. Different potential FDG uptake profiles, as a function of the microenvironment, were simulated. Predicted tumor doses for 50% control (TD50) in 2 Gy fractions were estimated for each assumed uptake profile and for various possible cell mixtures. The results support the hypothesis of an increased avidity of FDG for cells in the intermediate stress state (those receiving glucose but not oxygen) compared to well-oxygenated (and proliferating) cells.

Uptake of 2, 4-Dichlorophenoxyacetic acid by Pseudomonas fluorescens

USGS Publications Warehouse

Wedemeyer, G.A.

1966-01-01

Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “nonmetabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at pH values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carriermediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranylion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.

Uptake of 2,4-dichlorophenoxyacetic acid by Pseudomonas fluorescens

USGS Publications Warehouse

Wedemeyer, Gary

1966-01-01

Factors influencing the uptake of the sodium salt of 2,4-dichlorophenoxyacetic acid (2,4-D), under conditions in which no net metabolism occurred, were investigated in an effort to determine both the significance of “non-metabolic” uptake as a potential agent in reducing pesticide levels and the mechanisms involved. Uptake of 2,4-D was affected by pH, temperature, and the presence of other organic and inorganic compounds. Uptake was more pronounced at pH values less than 6, which implies that there may be some interaction between charged groups on the cell and the ionized carboxyl group of 2,4-D. Active transport, carrier-mediated diffusion, passive diffusion, and adsorption were considered as possible mechanisms. Though uptake was inhibited by glucose, sodium azide, and fluorodinitrobenzene (but not by uranyl ion), 2,4-D was not accumulated against a concentration gradient, a necessary consequence of an active transport system, nor was isotope counterflow found to occur. Thus, carrier-mediated diffusion was finally precluded, implying that uptake probably occurs by a two-step process: sorption onto the cell wall followed by passive diffusion into the cytoplasm.

Socio-Cognitive Determinants of the Mammography Screening Uptake among Iranian Women

PubMed

Mirzaei-Alavijeh, Mehdi; Ghorbani, Parvaneh; Jalilian, Farzad

2018-05-26

Background: Mammography screening uptake is the most effective method in breast cancer screening. The aim of this study was to determine the determinants related to mammography screening uptake among Iranian women based on the theory of planned behavior. Materials and Methods: This cross-sectional study was conducted among 408 women who referred to health centers in Kermanshah city, the western of Iran, during 2016. Participants filled out a self-administered questionnaire. Data were analyzed by SPSS version 21 using Pearson correlation, linear and logistic regression statistical tests at 95% significant level. Results: The mean age of participants was 39.61 years [SD: 8.28], ranged from 30 to 60 years. Almost 13% of the participants had already mammography screening uptake at least once. Perceived behavioral control (OR=1.229) and behavioral intention (OR=1.283) were the more influential predictors on mammography screening uptake. Conclusions: Based on result, it seems increase perceived behavior control toward mammography screening uptake may be usefulness in promotion of mammography screening uptake among Iranian women. Creative Commons Attribution License

Estimating the contribution of bryophytes to the atmospheric COS budget

NASA Astrophysics Data System (ADS)

Gimeno, Teresa; Ogee, Jerome; Wingate, Lisa

2017-04-01

In the past decade, global biogeochemical modellers have embraced enthusiastically the potential of carbonyl sulphide (COS) as a tracer for gross primary productivity (GPP). COS is the most abundant sulphur-containing gas in the atmosphere, it is produced mainly in the ocean and it is consumed by the biosphere, with terrestrial vegetation being the most important contributor. Plant COS uptake is proportional to photosynthetic CO2 withdraw and that is why measurements of the biosphere-atmosphere COS flux can serve a proxy for GPP. Plant COS uptake is mediated by the light-independent enzyme carbonic anhydrase that irreversibly hydrolyses COS into H2S, which is quickly utilised as a sulphur source. Currently, there are no described plant-processes with COS as a by-product and hence the atmospheric-plant COS flux is assumed unidirectional. So far, we had focused on characterizing plant COS uptake dynamics on vascular plants and previous studies are consistent with the unidirectional flux assumption. However, although early works on sulphur metabolism suggested non-vascular plants might not abide to this assumption, we lack estimates of COS uptake dynamics for non-vascular communities. Bryophytes are key constituents of biocrusts and non-vascular photoautrophic communities and in temperate and cold latitudes contribute significantly to ecosystem carbon and nutrient cycling. We expect that in these ecosystems the coupling between COS and CO2 uptake will be influenced by specific environmental cues that control gas-exchange in bryophytes. We expect tissue hydration to be the most influential driver on COS uptake. In contrast, light would constrain CO2 but not COS uptake and therefore we expect greater uncoupling of COS and CO2 in the dark than in vascular plants. We characterized COS and CO2 uptake dynamics in two broadly distributed bryophytes, with contrasting life forms and evolutionary origins: the liverwort Marchantia polymorpha and the feather moss Scleropodium purum. We measured CO2 and COS uptake with varying hydration status, light and temperatures. Our results showed that COS uptake is limited by either excess or low tissue water content, similar to photosynthetic CO2 uptake. We found that COS uptake continued in the dark, despite impaired photosynthesis. We demonstrate that the COS flux in bryophytes is not unidirectional and that COS emissions are temperature and not light driven. Our results also suggest that both the uptake and the emission components are subject to seasonal regulation, with both uptakes limited in winter by low temperatures. Our results serve as a first approximation to model seasonal COS fluxes from air temperature and humidity in bryophyte-dominated ecosystems in high latitudes. We suggest that bryophytes might have an unexpected contribution to the ecosystem COS budget: during the day, when photosynthesis dominates the CO2 flux, COS emission are enhanced by warmer temperatures, while COS uptake is limited by tissue hydration and bryophytes act a net COS source; at night when the temperatures are cool and humidity is high, COS uptake dominates and bryophytes would act a net COS sink, while continuing to emit CO2 from respiration.

Water Uptake Vs. Density and Conversion in Silicon Containing Cyanate Esters (Briefing Charts)

DTIC Science & Technology

2014-12-17

known that cyanate ester networks decrease in density as conversion increases, and that moisture uptake increases as conversion increases at...Charts 3. DATES COVERED (From - To) Dec 2014- Dec 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In-House Water Uptake Vs. Density and...Polymers and Composites, San Diego, CA, 15 December, 2014. PA#14581 14. ABSTRACT A study was conducted which explored the density, percent water uptake by

New and Simple Ways to Minimize Water Uptake and Hydrolytic Degradation in Cyanate Esters

DTIC Science & Technology

2016-01-27

Photo by U.S. Navy photo by Photographer’s Mate 1st Class Anibal Rivera (public domain). Importance of Moisture Uptake in Composite Component... Moisture Uptake in Thermoset Resins • Increasing conversion joins together more "loose ends" in the network, eliminating free space where water can be...public release; distribution is unlimited. PA Clearance #16205 6 Proposed Role of Vitrification in Controlling Moisture Uptake • Increasing conversions

Cardiac sarcoidosis demonstrated by Tl-201 and Ga-67 SPECT imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taki, J.; Nakajima, K.; Bunko, H.

1990-09-01

Ga-67 and Tl-201 SPECT was performed to evaluate cardiac sarcoidosis in a 15-year-old boy. Tl-201 SPECT imaging showed decreased uptake in the inferior to lateral wall and Ga-67 accumulation in the area of decreased Tl-201 uptake. These findings suggested cardiac sarcoidosis, and cardiac biopsy confirmed this diagnosis. After corticosteroid therapy, myocardial uptake of Ga-67 disappeared and myocardial TI-201 uptake became more homogeneous.

Uptake of gentamicin by separated, viable renal tubules from rabbits.

PubMed

Barza, M; Murray, T; Hamburger, R J

1980-04-01

The proximal renal tubules have a marked affinity for gentamicin; they also are the major site of nephrotoxicity caused by this drug. The uptake of radiolabeled gentamicin in separated, viable renal tubules prepared by enzymatic digestion of rabbit kidneys was studied. The preparations showed rapid initial uptake of gentamicin followed by continued slower uptake. Accumulation was not affected by pH, but was significantly inhibited by ouabain, dinitrophenol, anoxia, and hypothermia in the absence of evident cellular damage. At gentamicin concentrations of greater than 50 microgram/ml in the medium, there was competition for drug uptake. Gentamicin efflux in tubules that were taken from a medium containing antibiotic and placed into antibiotic-free fluid was slow and incomplete. From these data it appears that gentamicin uptake by separated renal tubules occurs by a process that requires metabolic energy; thereafter, the drug resides in a poorly exchangeable cellular pool.

( sup 14 C)-Sucrose uptake by guard cell protoplasts of pisum sativum, argenteum mutant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohrig, K.; Raschke, K.

1991-05-01

Guard cells rely on import for their supply with reduced carbon. The authors tested by silicone oil centrifugation the ability of guard cell protoplasts to accumulated ({sup 14}C)-sucrose. Uptake rates were corrected after measurement of {sup 14}C-sorbitol and {sup 3}H{sub 2}O spaces. Sucrose uptake followed biphasic kinetics, with a high-affinity component below 1 mM external sucrose (apparent K{sub m} 0.8 mM at 25C) and a low-affinity nonsaturable component above. Uptake depended on pH (optimum at pH 5.0). Variations in the concentrations of external KCl, CCCP, and valinomycin indicated that about one-half of the sucrose uptake rate could be related tomore » an electrochemical gradient across the plasmalemma. Total uptake rates measured at 5 mM external sucrose seem to be sufficient to replenish emptied plastids with starch within a few hours.« less

Uptake of VOC by sunflower

NASA Astrophysics Data System (ADS)

Folkers, A.; Miebach, M.; Kleist, E.; Wildt, J.

2003-04-01

To study potential VOC uptake by plants we exposed sunflower (Helianthus annuus) to different VOC in continuously stirred tank reactors. For many VOC like methanol, ethanol, acetone, methylvinylketone, isoprene or limonene no uptake was detectable within the accuracy of our analytic set up. Other VOC like hexanal, octanal, (E)-3-hexenol and nopinone were taken up by sunflower. The uptake was related to stomatal aperture. Obviously, these VOC enter the plants through stomata. In case of hexanal, octanal, and (E)-3-hexenol the uptake was only limited by stomatal aperture implying that these VOC are rapidly metabolised. For nopinone the uptake seems to be limited by a slow metabolization. Estimations of deposition velocities showed that dry deposition of these compounds cannot be neglected as sink if diffusion through stomata is the limiting step for dry deposition. In such cases the lifetime with respect to dry deposiotion is comparable to the lifetime with respect to oxidation by hydroxyl radicals.

A study of the uptake of chloroquine in malaria-infected erythrocytes. High and low affinity uptake and the influence of glucose and its analogues.

PubMed

Diribe, C O; Warhurst, D C

1985-09-01

A study of concentration- and substrate-dependence of chloroquine uptake has been carried out on mouse erythrocytes infected with the chloroquine-sensitive NK65 and the chloroquine-resistant RC strains of Plasmodium berghei. The presence of drug binding sites of high and low affinity in such strains of P. berghei was confirmed. High affinity uptake sites in cells parasitized with chloroquine-sensitive and chloroquine-resistant parasites have similar characteristics, but in the sensitive strain the major component of chloroquine-uptake is at high affinity and dependent on the availability of ATP whilst in the resistant strain the major component of uptake is at low affinity and independent of energy. An absolute increase in the quantity of the low affinity site in erythrocytes parasitized with chloroquine-resistant P. berghei was noted, which may be related to an increase in quantity of parasite membrane.

Abdominal and hepatic uptake of /sup 99m/Tc-pyrophosphate in neonatal necrotizing enterocolitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caride, V.J.; Touloukian, R.J.; Ablow, R.C.

1981-04-01

Abdominal /sup 99m/Tc-pyrophosphate (/sup 99m/Tc-PYP) scans were obtained in 15 neonates: 12 with neonatal necrotizing enterocolitis (NEC), two with osteomyelitis, and one with myocarditis. Ten of the babies with NEC had at least one positive scan; of these 10 studies, seven (Group A) showed both diffuse abdominal uptake and localized hepatic activity, two (Group B) showed abdominal uptake and questionable hepatic uptake, and one (Group C) demonstrated diffuse abdominal uptake only. The other two babies with NEC had normal scans (Group D). All NEC patients had normal scans. A patient with myocarditis had hepatic uptake of /sup 99m/Tc-PYP while themore » abdominal scan in the two infants with osteomyelitis was normal. These preliminary observations suggest that further study of a relationship between abdominal scan findings and the course of NEC is warranted.« less

Contribution of electrostatics to the binding of pancreatic-type ribonucleases to membranes.

PubMed

Sundlass, Nadia K; Eller, Chelcie H; Cui, Qiang; Raines, Ronald T

2013-09-17

Pancreatic-type ribonucleases show clinical promise as chemotherapeutic agents but are limited in efficacy by the inefficiency of their uptake by human cells. Cellular uptake can be increased by the addition of positive charges to the surface of ribonucleases, either by site-directed mutagenesis or by chemical modification. This observation has led to the hypothesis that ribonuclease uptake by cells depends on electrostatics. Here, we use a combination of experimental and computational methods to ascertain the contribution of electrostatics to the cellular uptake of ribonucleases. We focus on three homologous ribonucleases: Onconase (frog), ribonuclease A (cow), and ribonuclease 1 (human). Our results support the hypothesis that electrostatics are necessary for the cellular uptake of Onconase. In contrast, specific interactions with cell-surface components likely contribute more to the cellular uptake of ribonuclease A and ribonuclease 1 than do electrostatics. These findings provide insight for the design of new cytotoxic ribonucleases.

Characteristics of injury and recovery of net NO3- transport of barley seedlings from treatments of NaCl

NASA Technical Reports Server (NTRS)

Klobus, G.; Ward, M. R.; Huffaker, R. C.

1988-01-01

The nature of the injury and recovery of nitrate uptake (net uptake) from NaCl stress in young barley (Hordeum vulgare L, var CM 72) seedlings was investigated. Nitrate uptake was inhibited rapidly by NaCl, within 1 minute after exposure to 200 millimolar NaCl. The duration of exposure to saline conditions determined the time of recovery of NO3- uptake from NaCl stress. Recovery was dependent on the presence of NO3- and was inhibited by cycloheximide, 6-methylpurine, and cerulenin, respective inhibitors of protein, RNA, and sterol/fatty acid synthesis. These inhibitors also prevented the induction of the NO3- uptake system in uninduced seedlings. Uninduced seedlings exhibited endogenous NO3- transport activity that appeared to be constitutive. This constitutive activity was also inhibited by NaCl. Recovery of constitutive NO3- uptake did not require the presence of NO3-.

Cloning and functional characterization of the high-affinity K+ transporter HAK1 of pepper.

PubMed

Martínez-Cordero, M Angeles; Martínez, Vicente; Rubio, Francisco

2004-10-01

High-affinity K+ uptake in plants plays a crucial role in K+ nutrition and different systems have been postulated to contribute to the high-affinity K+ uptake. The results presented here with pepper (Capsicum annum) demonstrate that a HAK1-type transporter greatly contributes to the high-affinity K+ uptake observed in roots. Pepper plants starved of K+ for 3 d showed high-affinity K+ uptake (Km of 6 microM K+) that was very sensitive to NH and their roots expressed a high-affinity K+ transporter, CaHAK1, which clusters in group I of the KT/HAK/KUP family of transporters. When expressed in yeast ( Saccharomyces cerevisiae ), CaHAK1 mediated high-affinity K+ and Rb+ uptake with Km values of 3.3 and 1.9 microM, respectively. Rb+ uptake was competitively inhibited by micromolar concentrations of NH and Cs+, and by millimolar concentrations of Na+.

The significance of denitrifying polyphosphate accumulating organisms in biological nutrient removal activated sludge systems.

PubMed

Hu, Z R; Wentzel, M C; Ekama, G A

2002-01-01

In this paper the advantages and disadvantages of denitrifying PAOs (polyphosphate accumulating organisms) in conventional BNRAS (biological nutrient removal activated sludge) and external nitrification BNRAS (ENBNRAS) systems are evaluated, with experimental data exhibiting a range of anoxic P uptake from low (<10%) to very high (>60%). The results indicate that the specific denitrification rate of the PAOs on internally stored PHB COD is about 1/5th of that of the "ordinary" heterotrophic organisms on SBCOD, and the PAOs contribute little (maximum 20%) to the denitrification in BNRAS systems even when the anoxic P uptake is high (60% of the total P uptake). Considering the unpredictable nature of anoxic P uptake and the reduction in BEPR it causes compared with aerobic P uptake BEPR, it is concluded that anoxic P uptake does not add a significant advantage to the BNR system.

Is there a strategy I iron uptake mechanism in maize?

PubMed

Li, Suzhen; Zhou, Xiaojin; Chen, Jingtang; Chen, Rumei

2018-04-03

Iron is a metal micronutrient that is essential for plant growth and development. Graminaceous and nongraminaceous plants have evolved different mechanisms to mediate Fe uptake. Generally, strategy I is used by nongraminaceous plants like Arabidopsis, while graminaceous plants, such as rice, barley, and maize, are considered to use strategy II Fe uptake. Upon the functional characterization of OsIRT1 and OsIRT2 in rice, it was suggested that rice, as an exceptional graminaceous plant, utilizes both strategy I and strategy II Fe uptake systems. Similarly, ZmIRT1 and ZmZIP3 were identified as functional zinc and iron transporters in the maize genome, along with the determination of several genes encoding Zn and Fe transporters, raising the possibility that strategy I Fe uptake also occurs in maize. This mini-review integrates previous reports and recent evidence to obtain a better understanding of the mechanisms of Fe uptake in maize.

Hereditary dyserythropoiesis with abnormal membrane folate transport.

PubMed

Howe, R B; Branda, R F; Douglas, S D; Brunning, R D

1979-11-01

Dyserythropoiesis, which morphologically and serologically resembles congenital dyserythropoietic anemia type III but is not accompanied by anemia, is described in a young man. In addition to striking gigantism and multinuclearity of erythroid precursors, electron microscopy revealed widening of nuclear pores, nuclear clefts, and cytoplasmic inclusions. Membrane transport of 5-methyltetrahydrofolate by the patient's red cells was markedly reduced; total uptake, uptake velocity, and maximal velocity of uptake were all significantly less than in controls. In contrast, red cell uptake of pteroylglutamic acid was normal. Bone marrow cells in culture also showed decreased 5-methyltetrahydrofolate uptake, as well as very low thymidine incorporation. Because folate uptake by mitogen-stimulated lymphocytes was normal, the defect apparently does not involve all cell lines. These results suggest that a specific membrane defect, affecting the carrier system for reduced folate compounds, is present in this patient's erythrocytes, and perhaps, their bone marrow precursors.

Barriers to Male Involvement in Antenatal Care in Rural Mozambique

PubMed Central

Audet, Carolyn M.; Chire, Yazalde Manual; Vaz, Lara; Bechtel, Ruth; Carlson-Bremer, Daphne; Wester, C. William; Amico, K. Rivet; Calvo, Lázaro

2015-01-01

Low rates of antenatal care (ANC) service uptake limit the potential impact of mother-to-child HIV-prevention strategies. Zambézia province, Mozambique, has one of the lowest proportions of ANC uptake among pregnant women in the country, despite the availability of free services. We sought to identify factors influencing ANC service uptake (including HIV counseling and testing) through qualitative methods. Additionally, we encouraged discussion about strategies to improve uptake of services. We conducted 14 focus groups to explore community views on these topics. Based on thematic coding of discourse, two main themes emerged; (1) gender inequality in decision making and responsibility for pregnancy and (2) community beliefs that uptake of ANC services, particularly if supported by a male partner, reflects a woman’s HIV-positive status. Interventions to promote ANC uptake must work to shift cultural norms through male partner participation. Potential strategies to promote male engagement in ANC services are discussed. PMID:25854615

Nitrogen monoxide decreases iron uptake from transferrin but does not mobilise iron from prelabelled neoplastic cells.

PubMed

Richardson, D R; Neumannova, V; Ponka, P

1995-05-12

The effect of congeners of nitrogen monoxide (NO) on iron (Fe) uptake from 59Fe-125I-transferrin (Tf) and release of 59Fe from prelabelled cells have been investigated in SK-MEL-28 human melanoma cells, human K562 cells and mouse MDW-4 cells. These studies have been initiated as it has been suggested that the tumoricidal effects of NO may be mediated by its acting to release Fe from cells (Hibbs et al., 1984 Biochem. Biophys. Res. Commun. 123, 716-723; Hibbs et al., 1988 Biochem. Biophys. Res. Commun. 157, 87-94). The nitrosonium ion (NO+) generator, sodium nitroprusside (SNP), decreased 59Fe uptake by melanoma cells to 57% of the control without decreasing 125I-Tf uptake after a 4-h incubation with 59Fe-125-Tf (1.25 microM). Longer incubations up to 24 h decreased 59Fe uptake and also 125I-Tf uptake. Two breakdown products of SNP, ferricyanide and cyanide, had no effect on 59Fe uptake. In addition, photolysis of the SNP solution prevented the inhibition of 59Fe uptake, suggesting that NO was the active agent. Two nitric oxide (NO.) producing agents, 3-morpholinosydnonimine (SIN), and S-nitroso-N-acetylpenicillamine (SNAP), also decreased 59Fe uptake from 59Fe-125I-Tf. Superoxide dismutase increased the efficacy of SIN, and the NO-scavenger, oxyhaemoglobin, prevented the inhibition of 59Fe uptake mediated by SNAP, again suggesting that NO was the active agent. Furthermore, dialysis studies demonstrated that none of the NO-generating agents could remove 59Fe from 59Fe-125I-Tf, suggesting that the decrease in cellular Fe uptake observed was not due to NO releasing Fe from the Fe-binding sites of Tf. Despite the ability of NO-producing agents at inhibiting 59Fe uptake by cells, they could not remove significant amounts of 59Fe from melanoma cells prelabelled with either 59Fe-citrate or 59Fe-125I-Tf. Similar data were obtained using K562 and MDW-4 cells. Interestingly, the NO+ generating agent, SNP, had no effect on [3H]thymidine uptake. However, when SNP was converted to an NO. generator by the addition of 1 mM ascorbate, its effect was similar to the NO. generator, SNAP, markedly reducing [3H]thymidine incorporation to 33% of the control value. The addition of unlabelled diferric Tf (0.625 microM) to SNAP ameliorated its inhibitory effect on cellular [3H]thymidine uptake, suggesting that the interaction of NO. with Fe was of importance in the inhibition observed. The results are discussed in the context of the cytostatic potential of NO via its binding to Fe.

Multicenter Clinical Trials Using 18F-FDG PET to Measure Early Response to Oncologic Therapy: Effects of Injection-to-Acquisition Time Variability on Required Sample Size.

PubMed

Kurland, Brenda F; Muzi, Mark; Peterson, Lanell M; Doot, Robert K; Wangerin, Kristen A; Mankoff, David A; Linden, Hannah M; Kinahan, Paul E

2016-02-01

Uptake time (interval between tracer injection and image acquisition) affects the SUV measured for tumors in (18)F-FDG PET images. With dissimilar uptake times, changes in tumor SUVs will be under- or overestimated. This study examined the influence of uptake time on tumor response assessment using a virtual clinical trials approach. Tumor kinetic parameters were estimated from dynamic (18)F-FDG PET scans of breast cancer patients and used to simulate time-activity curves for 45-120 min after injection. Five-minute uptake time frames followed 4 scenarios: the first was a standardized static uptake time (the SUV from 60 to 65 min was selected for all scans), the second was uptake times sampled from an academic PET facility with strict adherence to standardization protocols, the third was a distribution similar to scenario 2 but with greater deviation from standards, and the fourth was a mixture of hurried scans (45- to 65-min start of image acquisition) and frequent delays (58- to 115-min uptake time). The proportion of out-of-range scans (<50 or >70 min, or >15-min difference between paired scans) was 0%, 20%, 44%, and 64% for scenarios 1, 2, 3, and 4, respectively. A published SUV correction based on local linearity of uptake-time dependence was applied in a separate analysis. Influence of uptake-time variation was assessed as sensitivity for detecting response (probability of observing a change of ≥30% decrease in (18)F-FDG PET SUV given a true decrease of 40%) and specificity (probability of observing an absolute change of <30% given no true change). Sensitivity was 96% for scenario 1, and ranged from 73% for scenario 4 (95% confidence interval, 70%-76%) to 92% (90%-93%) for scenario 2. Specificity for all scenarios was at least 91%. Single-arm phase II trials required an 8%-115% greater sample size for scenarios 2-4 than for scenario 1. If uptake time is known, SUV correction methods may raise sensitivity to 87%-95% and reduce the sample size increase to less than 27%. Uptake-time deviations from standardized protocols occur frequently, potentially decreasing the performance of (18)F-FDG PET response biomarkers. Correcting SUV for uptake time improves sensitivity, but algorithm refinement is needed. Stricter uptake-time control and effective correction algorithms could improve power and decrease costs for clinical trials using (18)F-FDG PET endpoints. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Glucose uptake of the muscle and adipose tissues in diabetes and obesity disease models: evaluation of insulin and β3-adrenergic receptor agonist effects by 18F-FDG.

PubMed

Ishino, Seigo; Sugita, Taku; Kondo, Yusuke; Okai, Mika; Tsuchimori, Kazue; Watanabe, Masanori; Mori, Ikuo; Hosoya, Masaki; Horiguchi, Takashi; Kamiguchi, Hidenori

2017-06-01

One of the major causes of diabetes and obesity is abnormality in glucose metabolism and glucose uptake in the muscle and adipose tissue based on an insufficient action of insulin. Therefore, many of the drug discovery programs are based on the concept of stimulating glucose uptake in these tissues. Improvement of glucose metabolism has been assessed based on blood parameters, but these merely reflect the systemic reaction to the drug administered. We have conducted basic studies to investigate the usefulness of glucose uptake measurement in various muscle and adipose tissues in pharmacological tests using disease-model animals. A radiotracer for glucose, 18 F-2-deoxy-2-fluoro-D-glucose ( 18 F-FDG), was administered to Wistar fatty rats (type 2 diabetes model), DIO mouse (obese model), and the corresponding control animals, and the basal glucose uptake in the muscle and adipose (white and brown) tissues were compared using biodistribution method. Moreover, insulin and a β3 agonist (CL316,243), which are known to stimulate glucose uptake in the muscle and adipose tissues, were administered to assess their effect. 18 F-FDG uptake in each tissue was measured as the radioactivity and the distribution was confirmed by autoradiography. In Wistar fatty rats, all the tissues measured showed a decrease in the basal level of glucose uptake when compared to Wistar lean rats. On the other hand, the same trend was observed only in the white adipose tissue in DIO mice, while brown adipose tissue showed increments in the basal glucose uptake in this model. Insulin administration stimulated glucose uptake in both Wistar lean and fatty rats, although the responses were inhibited in Wistar fatty rats. The same tendency was shown also in control mice, but clear increments in glucose uptake were not observed in the muscle and brown adipose tissue of DIO mice after insulin administration. β3 agonist administration showed the similar trend in Wistar lean and fatty rats as insulin, while the responses were inhibited in the adipose tissues of Wistar fatty rats. A system to monitor tissue glucose uptake with 18 F-FDG enabled us to detect clear differences in basal glucose uptake between disease-model animals and their corresponding controls. The responses in the tissues to insulin or β3 agonist could be identified. Taken as a whole, the biodistribution method with 18 F-FDG was confirmed to be useful for pharmacological evaluation of anti-diabetic or anti-obesity drugs using disease-model animals.

Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction

PubMed Central

Hummel, Scott L; Herald, John; Alpert, Craig; Gretebeck, Kimberlee A; Champoux, Wendy S; Dengel, Donald R; Vaitkevicius, Peter V; Alexander, Neil B

2016-01-01

Background Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. Methods Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). Results Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. Conclusions Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF. PMID:27594875

Submaximal oxygen uptake kinetics, functional mobility, and physical activity in older adults with heart failure and reduced ejection fraction.

PubMed

Hummel, Scott L; Herald, John; Alpert, Craig; Gretebeck, Kimberlee A; Champoux, Wendy S; Dengel, Donald R; Vaitkevicius, Peter V; Alexander, Neil B

2016-07-01

Submaximal oxygen uptake measures are more feasible and may better predict clinical cardiac outcomes than maximal tests in older adults with heart failure (HF). We examined relationships between maximal oxygen uptake, submaximal oxygen kinetics, functional mobility, and physical activity in older adults with HF and reduced ejection fraction. Older adults with HF and reduced ejection fraction (n = 25, age 75 ± 7 years) were compared to 25 healthy age- and gender-matched controls. Assessments included a maximal treadmill test for peak oxygen uptake (VO2peak), oxygen uptake kinetics at onset of and on recovery from a submaximal treadmill test, functional mobility testing [Get Up and Go (GUG), Comfortable Gait Speed (CGS), Unipedal Stance (US)], and self-reported physical activity (PA). Compared to controls, HF had worse performance on GUG, CGS, and US, greater delays in submaximal oxygen uptake kinetics, and lower PA. In controls, VO2peak was more strongly associated with functional mobility and PA than submaximal oxygen uptake kinetics. In HF patients, submaximal oxygen uptake kinetics were similarly associated with GUG and CGS as VO2peak, but weakly associated with PA. Based on their mobility performance, older HF patients with reduced ejection fraction are at risk for adverse functional outcomes. In this population, submaximal oxygen uptake measures may be equivalent to VO2 peak in predicting functional mobility, and in addition to being more feasible, may provide better insight into how aerobic function relates to mobility in older adults with HF.

Biodistribution of 99mTc-MAA on SPECT/CT performed for 90Y radioembolization therapy planning: a pictorial review.

PubMed

Bailey, J J; Dewaraja, Y; Hubers, D; Srinivasa, R N; Frey, K A

2017-10-01

To evaluate the frequency of 99mTc-MAA uptake in extrahepatic organs during 90Y radioembolization therapy planning. This retrospective case series of 70 subjects who underwent 99mTc-MAA hepatic artery perfusion studies between January 2014 and July 2016 for 90Y radioembolization therapy planning at our institution involved direct image review for all subjects, with endpoints recorded: lung shunt fraction, extrahepatic radiotracer uptake, time from MAA injection to imaging. Combined planar and SPECT/CT imaging findings in the 70 subjects demonstrated lung shunt fraction measurements of less than 10% in 53 (76%) subjects and greater than 10% in 17 (24%) subjects. All patients demonstrated renal cortical uptake, 23 (33%) demonstrated salivary gland uptake, 23 (33%) demonstrated thyroid uptake, and 32 (46%) demonstrated gastric mucosal uptake, with significant overlap between these groups. The range of elapsed times between MAA injection and initial imaging was 41-138 min, with a mean of 92 min. There was no correlation between time to imaging and the presence of extrahepatic radiotracer uptake at any site. During hepatic artery perfusion scanning for 90Y radioembolization therapy planning, extrahepatic uptake is common, particularly in the kidney, salivary gland, thyroid and gastric mucosa, and is hypothesized to result from breakdown of 99mTc-MAA over time. Given the breakdown to smaller aggregates and ultimately pertechnetate, this should not be a contraindication to actual Y-90 microsphere therapy. Although we found no correlation between time to imaging and extrahepatic uptake, most of our injection to imaging times were relatively short.

The kidney in vitamin B12 and folate homeostasis: characterization of receptors for tubular uptake of vitamins and carrier proteins.

PubMed

Birn, Henrik

2006-07-01

Over the past 10 years, animal studies have uncovered the molecular mechanisms for the renal tubular recovery of filtered vitamin and vitamin carrier proteins. Relatively few endocytic receptors are responsible for the proximal tubule uptake of a number of different vitamins, preventing urinary losses. In addition to vitamin conservation, tubular uptake by endocytosis is important to vitamin metabolism and homeostasis. The present review focuses on the receptors involved in renal tubular recovery of folate, vitamin B12, and their carrier proteins. The multiligand receptor megalin is important for the uptake and tubular accumulation of vitamin B12. During vitamin load, the kidney accumulates large amounts of free vitamin B12, suggesting a possible storage function. In addition, vitamin B12 is metabolized in the kidney, suggesting a role in vitamin homeostasis. The folate receptor is important for the conservation of folate, mediating endocytosis of the vitamin. Interaction between the structurally closely related, soluble folate-binding protein and megalin suggests that megalin plays an additional role in the uptake of folate bound to filtered folate-binding protein. A third endocytic receptor, the intrinsic factor-B12 receptor cubilin-amnionless complex, is essential to the renal tubular uptake of albumin, a carrier of folate. In conclusion, uptake is mediated by interaction with specific endocytic receptors also involved in the renal uptake of other vitamins and vitamin carriers. Little is known about the mechanisms regulating intracellular transport and release of vitamins, and whereas tubular uptake is a constitutive process, this may be regulated, e.g., by vitamin status.

Root traits explain observed tundra vegetation nitrogen uptake patterns: Implications for trait-based land models: Tundra N Uptake Model-Data Comparison

DOE PAGES

Zhu, Qing; Iversen, Colleen M.; Riley, William J.; ...

2016-12-23

Ongoing climate warming will likely perturb vertical distributions of nitrogen availability in tundra soils through enhancing nitrogen mineralization and releasing previously inaccessible nitrogen from frozen permafrost soil. But, arctic tundra responses to such changes are uncertain, because of a lack of vertically explicit nitrogen tracer experiments and untested hypotheses of root nitrogen uptake under the stress of microbial competition implemented in land models. We conducted a vertically explicit 15N tracer experiment for three dominant tundra species to quantify plant N uptake profiles. Then we applied a nutrient competition model (N-COM), which is being integrated into the ACME Land Model, tomore » explain the observations. Observations using an 15N tracer showed that plant N uptake profiles were not consistently related to root biomass density profiles, which challenges the prevailing hypothesis that root density always exerts first-order control on N uptake. By considering essential root traits (e.g., biomass distribution and nutrient uptake kinetics) with an appropriate plant-microbe nutrient competition framework, our model reasonably reproduced the observed patterns of plant N uptake. Additionally, we show that previously applied nutrient competition hypotheses in Earth System Land Models fail to explain the diverse plant N uptake profiles we observed. These results cast doubt on current climate-scale model predictions of arctic plant responses to elevated nitrogen supply under a changing climate and highlight the importance of considering essential root traits in large-scale land models. Finally, we provided suggestions and a short synthesis of data availability for future trait-based land model development.« less

Understanding low uptake of contraceptives in resource-limited settings: a mixed-methods study in rural Burundi.

PubMed

Ndayizigiye, M; Fawzi, M C Smith; Lively, C Thompson; Ware, N C

2017-03-15

Family planning can reduce deaths, improve health, and facilitate economic development in resource-limited settings. Yet, modern contraceptive methods are often underused. This mixed-methods study, conducted in rural Burundi, sought to explain low uptake of contraceptives by identifying utilization barriers. Results may inform development of family planning interventions in Burundi and elsewhere. We investigated uptake of contraceptives among women of reproductive age in two rural districts of Burundi, using an explanatory sequential, mixed-methods research design. We first assessed availability and utilization rates of modern contraceptives through a facility-based survey in 39 health clinics. Barriers to uptake of contraceptives were then explored through qualitative interviews (N = 10) and focus groups (N = 7). Contraceptives were generally available in the 39 clinics studied, yet uptake of family planning averaged only 2.96%. Greater uptake was positively associated with the number of health professionals engaged and trained in family planning service provision, and with the number of different types of contraceptives available. Four uptake barriers were identified: (1) lack of providers to administer contraception, (2) lack of fit between available and preferred contraceptive methods, (3) a climate of fear surrounding contraceptive use, and (4) provider refusal to offer family planning services. Where resources are scarce, availability of modern contraceptives alone will likely not ensure uptake. Interventions addressing multiple uptake barriers simultaneously have the greatest chance of success. In rural Burundi, examples are community distribution of contraceptive methods, public information campaigns, improved training for health professionals and community health workers, and strengthening of the health infrastructure.

Crassulacean Acid Metabolism in the Epiphyte Tillandsia usneoides L. (Spanish Moss) 1

PubMed Central

Martin, Craig E.; Siedow, James N.

1981-01-01

Patterns of CO2 exchange in Spanish moss under various experimental conditions were measured using an infrared gas analysis system. Plants were collected from a study site in North Carolina and placed in a gas exchange chamber for several days of continuous measurements. No substantial seasonal effects on CO2 exchange were observed. High rates of nocturnal CO2 uptake were observed under day/night temperature regimes of 25/10, 25/15, 25/20, 30/20, and 35/20 C; however, daytime temperatures of 40 C eliminated nighttime CO2 uptake and a nighttime temperature of 5 C eliminated nocturnal CO2 uptake, regardless of day temperature. Constant chamber conditions also inhibited nocturnal CO2 uptake. Constant high relative humidity (RH) slightly stimulated CO2 uptake while low nighttime RH reduced nocturnal CO2 uptake. Reductions in daytime irradiance to approximately 25% full sunlight had no effect on CO2 exchange. Continuous darkness resulted in continuous CO2 loss by the plants, but a CO2 exchange pattern similar to normal day/night conditions was observed under constant illumination. High tissue water content inhibited CO2 uptake. Wetting of the tissue at any time of day or night resulted in net CO2 loss. Abrupt increases in temperature or decreases in RH resulted in sharp decreases in net CO2 uptake. The results indicate that Spanish moss is tolerant of a wide range of temperatures, irradiances, and water contents. They also indicate that high nighttime RH is a prerequisite for high rates of CO2 uptake. PMID:16661912

Crassulacean Acid Metabolism in the Epiphyte Tillandsia usneoides L. (Spanish Moss) : RESPONSES OF CO(2) EXCHANGE TO CONTROLLED ENVIRONMENTAL CONDITIONS.

PubMed

Martin, C E; Siedow, J N

1981-08-01

Patterns of CO(2) exchange in Spanish moss under various experimental conditions were measured using an infrared gas analysis system. Plants were collected from a study site in North Carolina and placed in a gas exchange chamber for several days of continuous measurements. No substantial seasonal effects on CO(2) exchange were observed. High rates of nocturnal CO(2) uptake were observed under day/night temperature regimes of 25/10, 25/15, 25/20, 30/20, and 35/20 C; however, daytime temperatures of 40 C eliminated nighttime CO(2) uptake and a nighttime temperature of 5 C eliminated nocturnal CO(2) uptake, regardless of day temperature. Constant chamber conditions also inhibited nocturnal CO(2) uptake. Constant high relative humidity (RH) slightly stimulated CO(2) uptake while low nighttime RH reduced nocturnal CO(2) uptake.Reductions in daytime irradiance to approximately 25% full sunlight had no effect on CO(2) exchange. Continuous darkness resulted in continuous CO(2) loss by the plants, but a CO(2) exchange pattern similar to normal day/night conditions was observed under constant illumination. High tissue water content inhibited CO(2) uptake. Wetting of the tissue at any time of day or night resulted in net CO(2) loss. Abrupt increases in temperature or decreases in RH resulted in sharp decreases in net CO(2) uptake.The results indicate that Spanish moss is tolerant of a wide range of temperatures, irradiances, and water contents. They also indicate that high nighttime RH is a prerequisite for high rates of CO(2) uptake.

Preferential and Increased Uptake of Hydroxyl-Terminated PAMAM Dendrimers by Activated Microglia in Rabbit Brain Mixed Glial Culture.

PubMed

Alnasser, Yossef; Kambhampati, Siva P; Nance, Elizabeth; Rajbhandari, Labchan; Shrestha, Shiva; Venkatesan, Arun; Kannan, Rangaramanujam M; Kannan, Sujatha

2018-04-27

Polyamidoamine (PAMAM) dendrimers are multifunctional nanoparticles with tunable physicochemical features, making them promising candidates for targeted drug delivery in the central nervous system (CNS). Systemically administered dendrimers have been shown to localize in activated glial cells, which mediate neuroinflammation in the CNS. These dendrimers delivered drugs specifically to activated microglia, producing significant neurological improvements in multiple brain injury models, including in a neonatal rabbit model of cerebral palsy. To gain further insight into the mechanism of dendrimer cell uptake, we utilized an in vitro model of primary glial cells isolated from newborn rabbits to assess the differences in hydroxyl-terminated generation 4 PAMAM dendrimer (D4-OH) uptake by activated and non-activated glial cells. We used fluorescently-labelled D4-OH (D-Cy5) as a tool for investigating the mechanism of dendrimer uptake. D4-OH PAMAM dendrimer uptake was determined by fluorescence quantification using confocal microscopy and flow cytometry. Our results indicate that although microglial cells in the mixed cell population demonstrate early uptake of dendrimers in this in vitro system, activated microglia take up more dendrimer compared to resting microglia. Astrocytes showed delayed and limited uptake. We also illustrated the differences in mechanism of uptake between resting and activated microglia using different pathway inhibitors. Both resting and activated microglia primarily employed endocytotic pathways, which are enhanced in activated microglial cells. Additionally, we demonstrated that hydroxyl terminated dendrimers are taken up by primary microglia using other mechanisms including pinocytosis, caveolae, and aquaporin channels for dendrimer uptake.

Fatty acid transport protein-2 inhibitor Grassofermata/CB5 protects cells against lipid accumulation and toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saini, Nipun; Black, Paul N.; Montefusco, David

The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC{sub 50} 8–11 μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models formore » intestines, liver, muscle and pancreas. In adipocytes, uptake inhibition was less effective (IC{sub 50} 58 μM). Inhibition was specific for long chain fatty acids and was ineffective toward medium chain fatty acids, which are transported by diffusion. Kinetic analysis of Grassofermata-dependent FA transport inhibition verified a non-competitive mechanism. By comparison with Grassofermata, several atypical antipsychotic drugs previously implicated as inhibitors of FA uptake were ineffectual. In mice Grassofermata decreased absorption of {sup 13}C-oleate demonstrating its potential as a therapeutic agent. - Highlights: • Grassofermata is a small compound inhibitor of FATP2. • Uptake inhibition is specific for long chain fatty acids. • Uptake kinetics shows low specificity for adipocytes compared to other cell types. • Inhibition is by a non-competitive mechanism. • Atypical antipsychotics do not inhibit FA uptake by comparison with Grassofermata.« less

Stimulatory effect of insulin on glucose uptake by muscle involves the central nervous system in insulin-sensitive mice.

PubMed

Coomans, Claudia P; Biermasz, Nienke R; Geerling, Janine J; Guigas, Bruno; Rensen, Patrick C N; Havekes, Louis M; Romijn, Johannes A

2011-12-01

Insulin inhibits endogenous glucose production (EGP) and stimulates glucose uptake in peripheral tissues. Hypothalamic insulin signaling is required for the inhibitory effects of insulin on EGP. We examined the contribution of central insulin signaling on circulating insulin-stimulated tissue-specific glucose uptake. Tolbutamide, an inhibitor of ATP-sensitive K(+) channels (K(ATP) channels), or vehicle was infused into the lateral ventricle in the basal state and during hyperinsulinemic-euglycemic conditions in postabsorptive, chow-fed C57Bl/6J mice and in postabsorptive C57Bl/6J mice with diet-induced obesity. Whole-body glucose uptake was measured by d-[(14)C]glucose kinetics and tissue-specific glucose uptake by 2-deoxy-d-[(3)H]glucose uptake. During clamp conditions, intracerebroventricular administration of tolbutamide impaired the ability of insulin to inhibit EGP by ∼20%. In addition, intracerebroventricular tolbutamide diminished insulin-stimulated glucose uptake in muscle (by ∼59%) but not in heart or adipose tissue. In contrast, in insulin-resistant mice with diet-induced obesity, intracerebroventricular tolbutamide did not alter the effects of insulin during clamp conditions on EGP or glucose uptake by muscle. Insulin stimulates glucose uptake in muscle in part through effects via K(ATP) channels in the central nervous system, in analogy with the inhibitory effects of insulin on EGP. High-fat diet-induced obesity abolished the central effects of insulin on liver and muscle. These observations stress the role of central insulin resistance in the pathophysiology of diet-induced insulin resistance.

Post-flowering nitrate uptake in wheat is controlled by N status at flowering, with a putative major role of root nitrate transporter NRT2.1.

PubMed

Taulemesse, François; Le Gouis, Jacques; Gouache, David; Gibon, Yves; Allard, Vincent

2015-01-01

In bread wheat (Triticum aestivum L.), the simultaneous improvement of both yield and grain protein is difficult because of the strong negative relationship between these two traits. However, some genotypes deviate positively from this relationship and this has been linked to their ability to take up nitrogen (N) during the post-flowering period, regardless of their N status at flowering. The physiological and genetic determinants of post-flowering N uptake relating to N satiety are poorly understood. This study uses semi-hydroponic culture of cv. Récital under controlled conditions to explore these controls. The first objective was to record the effects of contrasting N status at flowering on post-flowering nitrate (NO₃⁻) uptake under non-limiting NO₃⁻ conditions, while following the expression of key genes involved in NO₃⁻ uptake and assimilation. We found that post-flowering NO₃⁻ uptake was strongly influenced by plant N status at flowering during the first 300-400 degree-days after flowering, overlapping with a probable regulation of nitrate uptake exerted by N demand for growth. The uptake of NO₃⁻ correlated well with the expression of the gene TaNRT2.1, coding for a root NO₃⁻ transporter, which seems to play a major role in post-flowering NO₃⁻ uptake. These results provide a useful knowledge base for future investigation of genetic variability in post-flowering N uptake and may lead to concomitant gains in both grain yield and grain protein in wheat.

Post-Flowering Nitrate Uptake in Wheat Is Controlled by N Status at Flowering, with a Putative Major Role of Root Nitrate Transporter NRT2.1

PubMed Central

Taulemesse, François; Le Gouis, Jacques; Gouache, David; Gibon, Yves; Allard, Vincent

2015-01-01

In bread wheat (Triticum aestivum L.), the simultaneous improvement of both yield and grain protein is difficult because of the strong negative relationship between these two traits. However, some genotypes deviate positively from this relationship and this has been linked to their ability to take up nitrogen (N) during the post-flowering period, regardless of their N status at flowering. The physiological and genetic determinants of post-flowering N uptake relating to N satiety are poorly understood. This study uses semi-hydroponic culture of cv. Récital under controlled conditions to explore these controls. The first objective was to record the effects of contrasting N status at flowering on post-flowering nitrate (NO3 -) uptake under non-limiting NO3 - conditions, while following the expression of key genes involved in NO3 - uptake and assimilation. We found that post-flowering NO3 - uptake was strongly influenced by plant N status at flowering during the first 300–400 degree-days after flowering, overlapping with a probable regulation of nitrate uptake exerted by N demand for growth. The uptake of NO3 - correlated well with the expression of the gene TaNRT2.1, coding for a root NO3 - transporter, which seems to play a major role in post-flowering NO3 - uptake. These results provide a useful knowledge base for future investigation of genetic variability in post-flowering N uptake and may lead to concomitant gains in both grain yield and grain protein in wheat. PMID:25798624

Quantitating Antibody Uptake In Vivo: Conditional Dependence on Antigen Expression Levels

PubMed Central

Thurber, Greg M.; Weissleder, Ralph

2010-01-01

Purpose Antibodies form an important class of cancer therapeutics, and there is intense interest in using them for imaging applications in diagnosis and monitoring of cancer treatment. Despite the expanding body of knowledge describing pharmacokinetic and pharmacodynamic interactions of antibodies in vivo, discrepancies remain over the effect of antigen expression level on tumoral uptake with some reports indicating a relationship between uptake and expression and others showing no correlation. Procedures Using a cell line with high EpCAM expression and moderate EGFR expression, fluorescent antibodies with similar plasma clearance were imaged in vivo. A mathematical model and mouse xenograft experiments were used to describe the effect of antigen expression on uptake of these high affinity antibodies. Results As predicted by the theoretical model, under subsaturating conditions, uptake of the antibodies in such tumors is similar because localization of both probes is limited by delivery from the vasculature. In a separate experiment, when the tumor is saturated, the uptake becomes dependent on the number of available binding sites. In addition, targeting of small micrometastases is shown to be higher than larger vascularized tumors. Conclusions These results are consistent with the prediction that high affinity antibody uptake is dependent on antigen expression levels for saturating doses and delivery for subsaturating doses. It is imperative for any probe to understand whether quantitative uptake is a measure of biomarker expression or transport to the region of interest. The data provide support for a predictive theoretical model of antibody uptake, enabling it to be used as a starting point for the design of more efficacious therapies and timely quantitative imaging probes. PMID:20809210

Quantitating antibody uptake in vivo: conditional dependence on antigen expression levels.

PubMed

Thurber, Greg M; Weissleder, Ralph

2011-08-01

Antibodies form an important class of cancer therapeutics, and there is intense interest in using them for imaging applications in diagnosis and monitoring of cancer treatment. Despite the expanding body of knowledge describing pharmacokinetic and pharmacodynamic interactions of antibodies in vivo, discrepancies remain over the effect of antigen expression level on tumoral uptake with some reports indicating a relationship between uptake and expression and others showing no correlation. Using a cell line with high epithelial cell adhesion molecule expression and moderate epidermal growth factor receptor expression, fluorescent antibodies with similar plasma clearance were imaged in vivo. A mathematical model and mouse xenograft experiments were used to describe the effect of antigen expression on uptake of these high-affinity antibodies. As predicted by the theoretical model, under subsaturating conditions, uptake of the antibodies in such tumors is similar because localization of both probes is limited by delivery from the vasculature. In a separate experiment, when the tumor is saturated, the uptake becomes dependent on the number of available binding sites. In addition, targeting of small micrometastases is shown to be higher than larger vascularized tumors. These results are consistent with the prediction that high affinity antibody uptake is dependent on antigen expression levels for saturating doses and delivery for subsaturating doses. It is imperative for any probe to understand whether quantitative uptake is a measure of biomarker expression or transport to the region of interest. The data provide support for a predictive theoretical model of antibody uptake, enabling it to be used as a starting point for the design of more efficacious therapies and timely quantitative imaging probes.

Effect of pH and calcium on short-term NO3- fluxes in roots of barley seedlings

NASA Technical Reports Server (NTRS)

Aslam, M.; Travis, R. L.; Huffaker, R. C.

1995-01-01

The effect of pH and Ca2+ on net NO3- uptake, influx, and efflux by intact roots of barley (Hordeum vulgare L.) seedlings was studied. Seedlings were induced with NO3- or NO2-. Net NO3- uptake and efflux, respectively, were determined by following its depletion from, and accumulation in, the external solution. Since roots of both uninduced and NO2(-)-induced seedlings contain little internal NO3- initial net uptake rates are equivalent to influx (M. Aslam, R.L. Travis, R.C. Huffaker [1994] Plant Physiol 106: 1293-1301). NO3-, uptake (influx) by these roots was little affected at acidic pH. In contrast, in NO3(-)-induced roots, which accumulate NO3-, net uptake rates decreased in response to acidic pH. Under these conditions, NO3- efflux was stimulated and was a function of root NO3- concentration. Conversely, at basic pH, NO3- uptake by NO3- and NO2(-)-induced and uninduced roots decreased, apparently because of the inhibition of influx. Calcium had little effect on NO3- uptake (influx) by NO2(-)-induced roots at either pH 3 or 6. However, in NO3(-)-induced roots, lack of Ca2+ at pH 3 significantly decreased net NO3- uptake and stimulated efflux. The results indicate that at acidic pH the decrease in net NO3- uptake is due to the stimulation of efflux, whereas at basic pH, it is due to the inhibition of influx.

Root traits explain observed tundra vegetation nitrogen uptake patterns: Implications for trait-based land models: Tundra N Uptake Model-Data Comparison

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Qing; Iversen, Colleen M.; Riley, William J.

Ongoing climate warming will likely perturb vertical distributions of nitrogen availability in tundra soils through enhancing nitrogen mineralization and releasing previously inaccessible nitrogen from frozen permafrost soil. But, arctic tundra responses to such changes are uncertain, because of a lack of vertically explicit nitrogen tracer experiments and untested hypotheses of root nitrogen uptake under the stress of microbial competition implemented in land models. We conducted a vertically explicit 15N tracer experiment for three dominant tundra species to quantify plant N uptake profiles. Then we applied a nutrient competition model (N-COM), which is being integrated into the ACME Land Model, tomore » explain the observations. Observations using an 15N tracer showed that plant N uptake profiles were not consistently related to root biomass density profiles, which challenges the prevailing hypothesis that root density always exerts first-order control on N uptake. By considering essential root traits (e.g., biomass distribution and nutrient uptake kinetics) with an appropriate plant-microbe nutrient competition framework, our model reasonably reproduced the observed patterns of plant N uptake. Additionally, we show that previously applied nutrient competition hypotheses in Earth System Land Models fail to explain the diverse plant N uptake profiles we observed. These results cast doubt on current climate-scale model predictions of arctic plant responses to elevated nitrogen supply under a changing climate and highlight the importance of considering essential root traits in large-scale land models. Finally, we provided suggestions and a short synthesis of data availability for future trait-based land model development.« less

Relation of organic contaminant equilibrium sorption and kinetic uptake in plants

USGS Publications Warehouse

Li, H.; Sheng, G.; Chiou, C.T.; Xu, O.

2005-01-01

Plant uptake is one of the environmental processes that influence contaminant fate. Understanding the magnitude and rate of plant uptake is critical to assessing potential crop contamination and the development of phytoremediation technologies. We determined (1) the partition-dominated equilibrium sorption of lindane (LDN) and hexachlorobenzene (HCB) by roots and shoots of wheat seedlings, (2) the kinetic uptake of LDN and HCB by roots and shoots of wheat seedlings, (3) the kinetic uptake of HCB, tetrachloroethylene (PCE), and trichloroethylene (TCE) by roots and shoots of ryegrass seedlings, and (4) the lipid, carbohydrate, and water contents of the plants. Although the determined sorption and the plant composition together suggest the predominant role of plant lipids for the sorption of LDN and HCB, the predicted partition with lipids of LDN and HCB using the octanol-water partition coefficients is notably lower than the measured sorption, due presumably to underestimation of the plant lipid contents and to the fact that octanol is less effective as a partition medium than plant lipids. The equilibrium sorption or the estimated partition can be viewed as the kinetic uptake limits. The uptakes of LDN, PCE, and TCE from water at fixed concentrations increased with exposure time in approach to steady states. The uptake of HCB did not reach a plateau within the tested time because of its exceptionally high partition coefficient. In all of the cases, the observed uptakes were lower than their respective limits, due presumably to contaminant dissipation in and limited water transpiration by the plants. ?? 2005 American Chemical Society.

Enhanced dopamine release by dopamine transport inhibitors described by a restricted diffusion model and fast scan cyclic voltammetry

PubMed Central

Hoffman, Alexander F.; Spivak, Charles E.; Lupica, Carl R.

2016-01-01

Fast-scan cyclic voltammetry (FSCV) using carbon fiber electrodes is widely used to rapidly monitor changes in dopamine (DA) levels in vitro and in vivo. Current analytical approaches utilize parameters such as peak oxidation current amplitude and decay times to estimate release and uptake processes, respectively. However, peak amplitude changes are often observed with uptake inhibitors, thereby confounding the interpretation of these parameters. To overcome this limitation, we demonstrate that a simple, 5 parameter, two compartment model mathematically describes DA signals as a balance of release (r/ke) and uptake (ku), summed with adsorption (kads and kdes) of DA to the carbon electrode surface. Using non-linear regression, we demonstrate that our model precisely describes measured DA signals obtained in brain slice recordings. The parameters extracted from these curves were then validated using pharmacological manipulations that selectively alter vesicular release or DA transporter (DAT)-mediated uptake. Manipulation of DA release through altered Ca2+/Mg2+ ratio or tetrodotoxin (TTX), reduced the release parameter with no effect on the uptake parameter. The DAT inhibitors methylenedioxypyrovalerone (MDPV), cocaine, and nomifensine significantly reduced uptake and increased vesicular DA release. In contrast, a low concentration of amphetamine reduced uptake but had no effect on DA release. Finally, the kappa-opioid receptor (KOR) agonist U50,488 significantly reduced vesicular DA release but had no effect on uptake. Together, these data demonstrate a novel analytical approach to distinguish the effects of manipulations on DA release or uptake that can be used to interpret FSCV data. PMID:27018734

Enhanced Dopamine Release by Dopamine Transport Inhibitors Described by a Restricted Diffusion Model and Fast-Scan Cyclic Voltammetry.

PubMed

Hoffman, Alexander F; Spivak, Charles E; Lupica, Carl R

2016-06-15

Fast-scan cyclic voltammetry (FSCV) using carbon fiber electrodes is widely used to rapidly monitor changes in dopamine (DA) levels in vitro and in vivo. Current analytical approaches utilize parameters such as peak oxidation current amplitude and decay times to estimate release and uptake processes, respectively. However, peak amplitude changes are often observed with uptake inhibitors, thereby confounding the interpretation of these parameters. To overcome this limitation, we demonstrate that a simple five-parameter, two-compartment model mathematically describes DA signals as a balance of release (r/ke) and uptake (ku), summed with adsorption (kads and kdes) of DA to the carbon electrode surface. Using nonlinear regression, we demonstrate that our model precisely describes measured DA signals obtained in brain slice recordings. The parameters extracted from these curves were then validated using pharmacological manipulations that selectively alter vesicular release or DA transporter (DAT)-mediated uptake. Manipulation of DA release through altering the Ca(2+)/Mg(2+) ratio or adding tetrodotoxin reduced the release parameter with no effect on the uptake parameter. DAT inhibitors methylenedioxypyrovalerone, cocaine, and nomifensine significantly reduced uptake and increased vesicular DA release. In contrast, a low concentration of amphetamine reduced uptake but had no effect on DA release. Finally, the kappa opioid receptor agonist U50,488 significantly reduced vesicular DA release but had no effect on uptake. Together, these data demonstrate a novel analytical approach to distinguish the effects of manipulations on DA release or uptake that can be used to interpret FSCV data.

Repeatability of Quantitative Whole-Body 18F-FDG PET/CT Uptake Measures as Function of Uptake Interval and Lesion Selection in Non-Small Cell Lung Cancer Patients.

PubMed

Kramer, Gerbrand Maria; Frings, Virginie; Hoetjes, Nikie; Hoekstra, Otto S; Smit, Egbert F; de Langen, Adrianus Johannes; Boellaard, Ronald

2016-09-01

Change in (18)F-FDG uptake may predict response to anticancer treatment. The PERCIST suggest a threshold of 30% change in SUV to define partial response and progressive disease. Evidence underlying these thresholds consists of mixed stand-alone PET and PET/CT data with variable uptake intervals and no consensus on the number of lesions to be assessed. Additionally, there is increasing interest in alternative (18)F-FDG uptake measures such as metabolically active tumor volume and total lesion glycolysis (TLG). The aim of this study was to comprehensively investigate the repeatability of various quantitative whole-body (18)F-FDG metrics in non-small cell lung cancer (NSCLC) patients as a function of tracer uptake interval and lesion selection strategies. Eleven NSCLC patients, with at least 1 intrathoracic lesion 3 cm or greater, underwent double baseline whole-body (18)F-FDG PET/CT scans at 60 and 90 min after injection within 3 d. All (18)F-FDG-avid tumors were delineated with an 50% threshold of SUVpeak adapted for local background. SUVmax, SUVmean, SUVpeak, TLG, metabolically active tumor volume, and tumor-to-blood and -liver ratios were evaluated, as well as the influence of lesion selection and 2 methods for correction of uptake time differences. The best repeatability was found using the SUV metrics of the averaged PERCIST target lesions (repeatability coefficients < 10%). The correlation between test and retest scans was strong for all uptake measures at either uptake interval (intraclass correlation coefficient > 0.97 and R(2) > 0.98). There were no significant differences in repeatability between data obtained 60 and 90 min after injection. When only PERCIST-defined target lesions were included (n = 34), repeatability improved for all uptake values. Normalization to liver or blood uptake or glucose correction did not improve repeatability. However, after correction for uptake time the correlation of SUV measures and TLG between the 60- and 90-min data significantly improved without affecting test-retest performance. This study suggests that a 15% change of SUVmean/SUVpeak at 60 min after injection can be used to assess response in advanced NSCLC patients if up to 5 PERCIST target lesions are assessed. Lower thresholds could be used in averaged PERCIST target lesions (<10%). © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Variability of the Intestinal Uptake of Lipids Is Genetically Determined in Mice

PubMed Central

Keelan, M.; Hui, D.Y.; Wild, G.; Clandinin, M.T.

2008-01-01

The response of the plasma cholesterol concentration to changes in dietary lipids varies widely in humans and animals. There are variations in the in vivo absorption of cholesterol between different strains of mice. This study was undertaken in three strains of inbred mice to test the hypotheses that: (i) there are strain differences in the in vitro uptake of fatty acids and cholesterol and (ii) the adaptability of the intestine to respond to variations in dietary lipids is genetically determined. An in vitro intestinal ring technique was used to assess the uptake of medium- and long-chain fatty acids and cholesterol into jejunum and ileum of adult DBA/2, C57BL6, and C57L/J mice. The jejunal uptake of cholesterol was similar in C57L/J, DBA/2, or C57BL6 fed ad libitum a low-fat (5.7% fat, no cholesterol) chow diet. This is in contrast to a previous demonstration that in vivo cholesterol absorption was lower in C57L/J than in the other murine strains. The jejunal uptake of several long-chain fatty acids was greater in DBA/2 fed for 4 wk the high-fat (15.8% fat and 1.25% cholesterol) as compared with the low-fat diet. Furthermore, on the high-fat diet, the uptake of many long-chain fatty acids was higher in DBA/2 than in C57BL6 or C57L/J. The differences in cholesterol and fatty acid uptake were not explained by variations in food uptake, body weight gain, or the weight of the intestine. In summary: (i) there are strain differences in the in vitro intestinal uptake of fatty acids but not of cholesterol; (ii) a high-fat diet enhances the uptake of long-chain fatty acids in only one of the three strains examined in this study; and (iii) the pattern of strain- and diet-associated alterations in the in vivo absorption of cholesterol differs from the pattern of changes observed in vitro. We speculate that genetic differences in cholesterol and fatty acid uptake are explained by variations in the expression of protein-mediated components of lipid uptake. PMID:10984106

Is the 6-minute walk test a reliable substitute for peak oxygen uptake in patients with dilated cardiomyopathy?

PubMed

Zugck, C; Krüger, C; Dürr, S; Gerber, S H; Haunstetter, A; Hornig, K; Kübler, W; Haass, M

2000-04-01

The 6-min walk test may serve as a more simple clinical tool to assess functional capacity in congestive heart failure than determination of peak oxygen uptake by cardiopulmonary exercise testing. The purpose of the study was to prospectively examine whether the distance ambulated during a 6-min walk test (i) correlates with peak oxygen uptake, (ii) allows peak oxygen uptake to be predicted, and (iii) provides prognostic information similar to peak oxygen uptake in patients with dilated cardiomyopathy and left ventricular ejection fraction < or = 35%. In 113 patients (age: 54+/-12 years, NYHA: 2.2+/-0.8) with dilated cardiomyopathy (left ventricular ejection fraction 19+/-7%) a 6-min walk test and cardiopulmonary exercise testing were performed. The 6-min walk test and peak oxygen uptake were closely correlated at the initial visit (r=0.68, n=113), as well as after 263+/-114 (r=0.71, n=28) and 381+/-170 days (r=0.74, n=14). During serial exercise testing the 6-min walk test allowed peak oxygen uptake to be reliably predicted (r=0.76 between calculated and real peak oxygen uptake). After 528+/-234 days, 42 patients were hospitalized due to worsening heart failure and/or died from cardiovascular causes. Compared to clinically stable patients, these 42 patients walked a shorter distance (423+/-104 vs 501+/-95 m, P<0.001) and had a lower peak oxygen uptake (12.7+/-4.0 vs 17.4 + 5.6 ml x min(-1) x kg(-1), P<0.001). By univariate analysis the 6-min walk test outperformed other prognostic parameters such as left ventricular ejection fraction, cardiac index and plasma norepinephrine concentration and conferred a prognostic power similar to peak oxygen uptake. This predictive value could be further improved in a multivariate model, by combining the 6-min walk test with independent variables, such as left ventricular ejection fraction or cardiac index. The 6-min walk test correlated with peak oxygen uptake when tested serially over the course of the disease. Although both tests define two distinct domains of functional capacity, the 6-min walk test provides prognostic information very similar to peak oxygen uptake in congestive heart failure patients with dilated cardiomyopathy.

Simulations and field observations of root water uptake in plots with different soil water availability.

NASA Astrophysics Data System (ADS)

Cai, Gaochao; Vanderborght, Jan; Couvreur, Valentin; Javaux, Mathieu; Vereecken, Harry

2015-04-01

Root water uptake is a main process in the hydrological cycle and vital for water management in agronomy. In most models of root water uptake, the spatial and temporal soil water status and plant root distributions are required for water flow simulations. However, dynamic root growth and root distributions are not easy and time consuming to measure by normal approaches. Furthermore, root water uptake cannot be measured directly in the field. Therefore, it is necessary to incorporate monitoring data of soil water content and potential and root distributions within a modeling framework to explore the interaction between soil water availability and root water uptake. But, most models are lacking a physically based concept to describe water uptake from soil profiles with vertical variations in soil water availability. In this contribution, we present an experimental setup in which root development, soil water content and soil water potential are monitored non-invasively in two field plots with different soil texture and for three treatments with different soil water availability: natural rain, sheltered and irrigated treatment. Root development is monitored using 7-m long horizontally installed minirhizotubes at six depths with three replicates per treatment. The monitoring data are interpreted using a model that is a one-dimensional upscaled version of root water uptake model that describes flow in the coupled soil-root architecture considering water potential gradients in the system and hydraulic conductances of the soil and root system (Couvreur et al., 2012). This model approach links the total root water uptake to an effective soil water potential in the root zone. The local root water uptake is a function of the difference between the local soil water potential and effective root zone water potential so that compensatory uptake in heterogeneous soil water potential profiles is simulated. The root system conductance is derived from inverse modelling using measurements of soil water potentials, water contents, and root distributions. The results showed that this modelling approach reproduced soil water dynamics well in the different plots and treatments. Root water uptake reduced when the effective soil water potential decreased to around -70 to -100 kPa in the root zone. Couvreur, V., Vanderborght, J., and Javaux, M.: A simple three dimensional macroscopic root water uptake model based on the hydraulic architecture approach, Hydrol. Earth Syst. Sci., 16, 2957-2971, doi:10.5194/hess-16-2957-2012, 2012.

Repeated Positron Emission Tomography-Computed Tomography and Perfusion-Computed Tomography Imaging in Rectal Cancer: Fluorodeoxyglucose Uptake Corresponds With Tumor Perfusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janssen, Marco H.M., E-mail: marco.janssen@maastro.nl; Aerts, Hugo J.W.L.; Buijsen, Jeroen

2012-02-01

Purpose: The purpose of this study was to analyze both the intratumoral fluorodeoxyglucose (FDG) uptake and perfusion within rectal tumors before and after hypofractionated radiotherapy. Methods and Materials: Rectal cancer patients, referred for preoperative hypofractionated radiotherapy (RT), underwent FDG-positron emission tomography (PET)-computed tomography (CT) and perfusion-CT (pCT) imaging before the start of hypofractionated RT and at the day of the last RT fraction. The pCT-images were analyzed using the extended Kety model, quantifying tumor perfusion with the pharmacokinetic parameters K{sup trans}, v{sub e}, and v{sub p}. The mean and maximum FDG uptake based on the standardized uptake value (SUV) andmore » transfer constant (K{sup trans}) within the tumor were correlated. Also, the tumor was subdivided into eight subregions and for each subregion the mean and maximum SUVs and K{sup trans} values were assessed and correlated. Furthermore, the mean FDG uptake in voxels presenting with the lowest 25% of perfusion was compared with the FDG uptake in the voxels with the 25% highest perfusion. Results: The mean and maximum K{sup trans} values were positively correlated with the corresponding SUVs ({rho} = 0.596, p = 0.001 and {rho} = 0.779, p < 0.001). Also, positive correlations were found for K{sup trans} values and SUVs within the subregions (mean, {rho} = 0.413, p < 0.001; and max, {rho} = 0.540, p < 0.001). The mean FDG uptake in the 25% highest-perfused tumor regions was significantly higher compared with the 25% lowest-perfused regions (10.6% {+-} 5.1%, p = 0.017). During hypofractionated radiotherapy, stable mean (p = 0.379) and maximum (p = 0.280) FDG uptake levels were found, whereas the mean (p = 0.040) and maximum (p = 0.003) K{sup trans} values were found to significantly increase. Conclusion: Highly perfused rectal tumors presented with higher FDG-uptake levels compared with relatively low perfused tumors. Also, intratumor regions with a high FDG uptake demonstrated with higher levels of perfusion than regions with a relatively low FDG-uptake. Early after hypofractionated RT, stable FDG uptake levels were found, whereas tumor perfusion was found to significantly increase.« less

Biological-Mathematical Modeling of Chronic Toxicity.

DTIC Science & Technology

1981-07-22

34Mathematical Model of Uptake and Distribution," Uptake and Distribution of Anesthetic Agents, E. M. Papper and R. J. Kitz (Editors, McGraw-Hill Book Co., Inc...distribution, In: Papper , E.M. and Kltz, R.J.(eds.) Uptake and distribution of anesthetic agents, McGraw- Hill, New York, p. 72 3. Plpleson, W.W...1963) Quantitative prediction of anesthetic concentrations. In: Papper , E.M. and Kitz, R.J. (eds.) Uptake and distribution of anesthetic agents, McGraw

Loss of ATP-dependent lysine uptake in the vacuolar membrane vesicles of Saccharomyces cerevisiae ypq1∆ mutant.

PubMed

Sekito, Takayuki; Nakamura, Kyosuke; Manabe, Kunio; Tone, Junichi; Sato, Yumika; Murao, Nami; Kawano-Kawada, Miyuki; Kakinuma, Yoshimi

2014-01-01

Saccharomyces cerevisiae Ypq1p is a vacuolar membrane protein of the PQ-loop protein family. We found that ATP-dependent uptake activities of amino acids by vacuolar membrane vesicles were impaired by ypq1∆ mutation. Loss of lysine uptake was most remarkable, and the uptake was recovered by overproduction of Ypq1p. Ypq1p is thus involved in transport of amino acids into vacuoles.

Interactions Between Structure and Processing that Control Moisture Uptake in High-Performance Polycyanurates (Briefing Charts)

DTIC Science & Technology

2015-03-24

distribution is unlimited.  . Interactions Between Structure and Processing that Control Moisture Uptake in High-Performance Polycyanurates Presenter: Dr...Edwards AFB, CA 4 California State University, Long Beach, CA 90840 2 Outline: Basic Studies of Moisture Uptake in Cyanate Ester Networks • Background...Motivation • SOTA Theories of Moisture Uptake in Thermosetting Networks • New Tools and New Discoveries • Unresolved Issues and Ways to Address Them

Inoculation with arbuscular mycorrhizae does not improve 137Cs uptake in crops grown in the Chernobyl region.

PubMed

Vinichuk, M; Mårtensson, A; Rosén, K

2013-12-01

Methods for cleaning up radioactive contaminated soils are urgently needed. In this study we investigated whether the use of arbuscular mycorrhizal (AM) fungi can improve (137)Cs uptake by crops. Barley, cucumber, perennial ryegrass, and sunflower were inoculated with AM fungi and grown in low-level radionuclide contaminated soils in a field experiment 70 km southwest of Chernobyl, Ukraine, during two successive years (2009-2010). Roots of barley, cucumber and sunflower plants were slightly or moderately infected with AM fungus and root infection frequency was negatively or non-correlated with (137)Cs uptake by plants. Roots of ryegrass were moderately infected with AM fungus and infection frequency was moderately correlated with (137)Cs uptake by ryegrass. The application of AM fungi to soil in situ did not enhance radionuclide plant uptake or biomass. The responsiveness of host plants and AM fungus combination to (137)Cs uptake varied depending on the soil, although mycorrhization of soil in the field was conditional and did not facilitate the uptake of radiocesium. The total amount of (137)Cs uptake by plants growing on inoculated soil was equal to amounts in plant cultivated on non-inoculated soil. Thus, the use of AM fungi in situ for bioremediation of soil contaminated with a low concentration of (137)Cs could not be recommended. Copyright © 2013 Elsevier Ltd. All rights reserved.

The contribution of water soluble and water insoluble organic fractions to oxygen uptake rate during high rate composting.

PubMed

Giuliana, D'Imporzano; Fabrizio, Adani

2007-02-01

This study aims to establish the contribution of the water soluble and water insoluble organic fractions to total oxygen uptake rate during high rate composting process of a mixture of organic fraction of municipal solid waste and lignocellulosic material. This mixture was composted using a 20 l self-heating pilot scale composter for 250 h. The composter was fully equipped to record both the biomass-temperature and oxygen uptake rate. Representative compost samples were taken at 0, 70, 100, 110, 160, and 250 h from starting time. Compost samples were fractionated in water soluble and water insoluble fractions. The water soluble fraction was then fractionated in hydrophilic, hydrophobic, and neutral hydrophobic fractions. Each fraction was then studied using quantitative (total organic carbon) and qualitative analysis (diffuse reflectance infrared spectroscopy and biodegradability test). Oxygen uptake rates were high during the initial stages of the process due to rapid degradation of the soluble degradable organic fraction (hydrophilic plus hydrophobic fractions). Once this fraction was depleted, polymer hydrolysis accounted for most of the oxygen uptake rate. Finally, oxygen uptake rate could be modeled using a two term kinetic. The first term provides the oxygen uptake rate resulting from the microbial growth kinetic type on easily available, no-limiting substrate (soluble fraction), while the second term considers the oxygen uptake rate caused by the degradation of substrate produced by polymer hydrolysis.

Involvement of Silicon Influx Transporter OsNIP2;1 in Selenite Uptake in Rice1[W][OA

PubMed Central

Zhao, Xue Qiang; Mitani, Namiki; Yamaji, Naoki; Shen, Ren Fang; Ma, Jian Feng

2010-01-01

Rice (Oryza sativa) as a staple food, provides a major source of dietary selenium (Se) for humans, which essentially requires Se, however, the molecular mechanism for Se uptake is still poorly understood. Herein, we show evidence that the uptake of selenite, a main bioavailable form of Se in paddy soils, is mediated by a silicon (Si) influx transporter Lsi1 (OsNIP2;1) in rice. Defect of OsNIP2;1 resulted in a significant decrease in the Se concentration of the shoots and xylem sap when selenite was given. However, there was no difference in the Se concentration between the wild-type rice and mutant of OsNIP2;1 when selenate was supplied. A short-term uptake experiment showed that selenite uptake greatly increased with decreasing pH in the external solution. Si as silicic acid did not inhibit the Se uptake from selenite in both rice and yeast (Saccharomyces cerevisiae) at low pHs. Expression of OsNIP2;1 in yeast enhanced the selenite uptake at pH 3.5 and 5.5 but not at pH 7.5. On the other hand, defect of Si efflux transporter Lsi2 did not affect the uptake of Se either from selenite or selenate. Taken together, our results indicate that Si influx transporter OsNIP2;1 is permeable to selenite. PMID:20498338

Leucine facilitates the insulin-stimulated glucose uptake and insulin signaling in skeletal muscle cells: involving mTORC1 and mTORC2.

PubMed

Liu, Hui; Liu, Rui; Xiong, Yufang; Li, Xiang; Wang, Xiaolei; Ma, Yan; Guo, Huailan; Hao, Liping; Yao, Ping; Liu, Liegang; Wang, Di; Yang, Xuefeng

2014-08-01

Leucine, a branched-chain amino acid, has been shown to promote glucose uptake and increase insulin sensitivity in skeletal muscle, but the exact mechanism remains unestablished. We addressed this issue in cultured skeletal muscle cells in this study. Our results showed that leucine alone did not have an effect on glucose uptake or phosphorylation of protein kinase B (AKT), but facilitated the insulin-induced glucose uptake and AKT phosphorylation. The insulin-stimulated glucose uptake and AKT phosphorylation were inhibited by the phosphatidylinositol 3-kinase inhibitor, wortmannin, but the inhibition was partially reversed by leucine. The inhibitor of mammalian target of rapamycin complex 1 (mTORC1), rapamycin, had no effect on the insulin-stimulated glucose uptake, but eliminated the facilitating effect of leucine in the insulin-stimulated glucose uptake and AKT phosphorylation. In addition, leucine facilitation of the insulin-induced AKT phosphorylation was neutralized by knocking down the core component of the mammalian target of rapamycin complex 2 (mTORC2) with specific siRNA. Together, these findings show that leucine can facilitate the insulin-induced insulin signaling and glucose uptake in skeletal muscle cells through both mTORC1 and mTORC2, implicating the potential importance of this amino acid in glucose homeostasis and providing new mechanistic insights.

Impact of a Pharmacy Benefit Change on New Use of Mail Order Pharmacy among Diabetes Patients: The Diabetes Study of Northern California (DISTANCE)

PubMed Central

Karter, Andrew J; Parker, Melissa M; Duru, O Kenrik; Schillinger, Dean; Adler, Nancy E; Moffet, Howard H; Adams, Alyce S; Chan, James; Herman, Willam H; Schmittdiel, Julie A

2015-01-01

Objective To assess the impact of a pharmacy benefit change on mail order pharmacy (MOP) uptake. Data Sources/Study Setting Race-stratified, random sample of diabetes patients in an integrated health care delivery system. Study Design In this natural experiment, we studied the impact of a pharmacy benefit change that conditionally discounted medications if patients used MOP and prepaid two copayments. We compared MOP uptake among those exposed to the benefit change (n = 2,442) and the reference group with no benefit change (n = 8,148), and estimated differential MOP uptake across social strata using a difference-in-differences framework. Data Collection/Extraction Methods Ascertained MOP uptake (initiation among previous nonusers). Principal Findings Thirty percent of patients started using MOP after receiving the benefit change versus 9 percent uptake among the reference group (p < .0001). After adjustment, there was a 26 percentage point greater MOP uptake (benefit change effect). This benefit change effect was significantly smaller among patients with inadequate health literacy (15 percent less), limited English proficiency (14 percent less), and among Latinos and Asians (24 and 16 percent less compared to Caucasians). Conclusions Conditionally discounting medications delivered by MOP effectively stimulated MOP uptake overall, but it unintentionally widened previously existing social gaps in MOP use because it stimulated less MOP uptake in vulnerable populations. PMID:25131156

Elucidating the Function of Penetratin and a Static Magnetic Field in Cellular Uptake of Magnetic Nanoparticles

PubMed Central

Chaudhary, Suman; Smith, Carol Anne; del Pino, Pablo; de la Fuente, Jesus M.; Mullin, Margaret; Hursthouse, Andrew; Stirling, David; Berry, Catherine C.

2013-01-01

Nanotechnology plays an increasingly important role in the biomedical arena. In particular, magnetic nanoparticles (mNPs) have become important tools in molecular diagnostics, in vivo imaging and improved treatment of disease, with the ultimate aim of producing a more theranostic approach. Due to their small sizes, the nanoparticles can cross most of the biological barriers such as the blood vessels and the blood brain barrier, thus providing ubiquitous access to most tissues. In all biomedical applications maximum nanoparticle uptake into cells is required. Two promising methods employed to this end include functionalization of mNPs with cell-penetrating peptides to promote efficient translocation of cargo into the cell and the use of external magnetic fields for enhanced delivery. This study aimed to compare the effect of both penetratin and a static magnetic field with regards to the cellular uptake of 200 nm magnetic NPs and determine the route of uptake by both methods. Results demonstrated that both techniques increased particle uptake, with penetratin proving more cell specific. Clathrin- medicated endocytosis appeared to be responsible for uptake as shown via PCR and western blot, with Pitstop 2 (known to selectively block clathrin formation) blocking particle uptake. Interestingly, it was further shown that a magnetic field was able to reverse or overcome the blocking, suggesting an alternative route of uptake. PMID:24275948

Active uptake system for substance P carboxy-terminal heptapeptide (5-11) into a fraction from rabbit enriched in glial cells.

PubMed

Inoue, A; Nakata, Y; Yajima, H; Segawa, T

1984-10-01

In the present study, we demonstrated the existence of an active uptake system for substance P carboxy-terminal heptapeptide, (5-11)SP. When a fraction from rabbit brain enriched in glial cells was incubated with [3H] (5-11)SP, an uptake of [3H](5-11)SP was observed. The uptake system has the properties of an active transport mechanism. Kinetic analysis indicated two components of [3H](5-11)SP uptake, one representing a high and the other a low affinity transport system. After unilateral ablation of the striatum, approximately 30% of the high affinity [3H](5-11)SP uptake capacity of substantia nigra slices disappeared. The subcellular distribution of the high affinity uptake indicated that [3H] 5-hydroxytryptamine was taken up mostly into the P2B fraction (synaptosomal fraction), whereas [3H](5-11)SP was taken up into the P2A fraction (myelin fraction) to the same extent as into the P2B fraction. These results suggest that when SP is released from nerve terminals, it is hydrolysed into (5-11)SP, which is in turn accumulated into glial cells as well as nerve terminals and that this high affinity uptake mechanism may play an important role in terminating the synaptic action of SP.

Lectins as endocytic ligands: an assessment of lectin binding and uptake to rabbit conjunctival epithelial cells.

PubMed

Qaddoumi, Mohamed; Lee, Vincent H L

2004-07-01

To investigate the binding and uptake pattern of three plant lectins in rabbit conjunctival epithelial cells (RCECs) with respect to their potential for enhancing cellular macromolecular uptake. Three fluorescein-labeled plant lectins (Lycoperison esculentum, TL; Solanum tuberosum, STL; and Ulex europaeus 1, UEA-1) were screened with respect to time-, concentration-, and temperature-dependent binding and uptake. Chitin (30 mg/ml) and L-alpha-fucose (10 mM) were used as inhibitory sugars to correct for nonspecific binding of TL or STL and UEA-1, respectively. Confocal microscopy was used to confirm internalization of STL. The binding and uptake of all three lectins in RCECs was time-dependent (reaching a plateau at 1-2 h period) and saturable at 1-h period. The rank order of affinity constants (km) was STL>TL>UEA-1 with values of 0.39>0.48>4.81 microM, respectively. However, maximal, specific binding/uptake potential was in the order UEA-1>STL>TL with values of 53.7, 52.3, and 15.0 nM/mg of cell protein, respectively. Lectins showed temperature dependence in their uptake, with STL exhibiting the highest endocytic capacity. Internalized STL was visualized by confocal microscopy to be localized to the cell membrane and cytoplasm. Based on favorable binding and uptake characteristics, potato lectin appears to be a useful candidate for further investigation as an ocular drug delivery system.

Roles of sulfuric acid in elemental mercury removal by activated carbon and sulfur-impregnated activated carbon.

PubMed

Morris, Eric A; Kirk, Donald W; Jia, Charles Q; Morita, Kazuki

2012-07-17

This work addresses the discrepancy in the literature regarding the effects of sulfuric acid (H(2)SO(4)) on elemental Hg uptake by activated carbon (AC). H(2)SO(4) in AC substantially increased Hg uptake by absorption particularly in the presence of oxygen. Hg uptake increased with acid amount and temperature exceeding 500 mg-Hg/g-AC after 3 days at 200 °C with AC treated with 20% H(2)SO(4). In the absence of other strong oxidizers, oxygen was able to oxidize Hg. Upon oxidation, Hg was more readily soluble in the acid, greatly enhancing its uptake by acid-treated AC. Without O(2), S(VI) in H(2)SO(4) was able to oxidize Hg, thus making it soluble in H(2)SO(4). Consequently, the presence of a bulk H(2)SO(4) phase within AC pores resulted in an orders of magnitude increase in Hg uptake capacity. However, the bulk H(2)SO(4) phase lowered the AC pore volume and could block the access to the active surface sites and potentially hinder Hg uptake kinetics. AC treated with SO(2) at 700 °C exhibited a much faster rate of Hg uptake attributed to sulfur functional groups enhancing adsorption kinetics. SO(2)-treated carbon maintained its fast uptake kinetics even after impregnation by 20% H(2)SO(4).

Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

PubMed

Powell, Joshua; Luh, Jeanne; Coronell, Orlando

2014-01-01

We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

Cell-free DNA testing after combined test: factors affecting the uptake.

PubMed

Maiz, Nerea; Alzola, Irune; Murua, Emerson J; Rodríguez Santos, Javier

2016-11-01

First, to assess what was the uptake of cell free DNA (cfDNA) testing after a combined test and the maternal and fetal factors that influenced this decision, and second, to assess the uptake and factors that influence the choice of invasive testing. This observational retrospective study included 1083 singleton pregnancies who had a combined test for screening for Down syndrome between 11 (+) (0) and 13 (+) (6) weeks. Multivariate logistic regression analysis was used to determine which factors affected the uptake of cfDNA test and invasive testing among risk for trisomies 21, 18, and 13, maternal characteristics and fetal nuchal translucency (NT) thickness. Two-hundred fifty-seven (23.7%) women had a cfDNA test, 89 (8.2%) had an invasive test, and 737 (68.1%) had no further test. The uptake of cfDNA increased with the risk for trisomies (p < 0.001), maternal age (p = 0.013), and was higher in nulliparous women (p = 0.004). The uptake of invasive test increased with the risk for trisomies (p < 0.001) and NT thickness (p < 0.001). This study shows that the uptake of cfDNA testing increases with the risk for trisomies, maternal age, and is higher in nulliparous, whereas the uptake of invasive testing increases with the risk for trisomies and NT thickness.

Exercise-induced muscle glucose uptake in mice with graded, muscle-specific GLUT-4 deletion.

PubMed

Howlett, Kirsten F; Andrikopoulos, Sofianos; Proietto, Joseph; Hargreaves, Mark

2013-08-01

To investigate the importance of the glucose transporter GLUT-4 for muscle glucose uptake during exercise, transgenic mice with skeletal muscle GLUT-4 expression approximately 30-60% of normal (CON) and approximately 5-10% of normal (KO) were generated using the Cre/Lox system and compared with wild-type (WT) mice during approximately 40 min of treadmill running (KO: 37.7 ± 1.3 min; WT: 40 min; CON: 40 min, P = 0.18). In WT and CON animals, exercise resulted in an overall increase in muscle glucose uptake. More specifically, glucose uptake was increased in red gastrocnemius of WT mice and in the soleus and red gastrocnemius of CON mice. In contrast, the exercise-induced increase in muscle glucose uptake in all muscles was completely abolished in KO mice. Muscle glucose uptake increased during exercise in both red and white quadriceps of WT mice, while the small increases in CON mice were not statistically significant. In KO mice, there was no change at all in quadriceps muscle glucose uptake. No differences in muscle glycogen use during exercise were observed between any of the groups. However, there was a significant increase in plasma glucose levels after exercise in KO mice. The results of this study demonstrated that a reduction in skeletal muscle GLUT-4 expression to approximately 10% of normal levels completely abolished the exercise-induced increase in muscle glucose uptake.

Routes of uptake of diclofenac, fluoxetine, and triclosan into sediment-dwelling worms.

PubMed

Karlsson, Maja V; Marshall, Stuart; Gouin, Todd; Boxall, Alistair B A

2016-04-01

The present study investigated the route and degree of uptake of 2 ionizable pharmaceuticals (diclofenac and fluoxetine) and 1 ionizable compound used in personal care products (triclosan) into the sediment-dwelling worm Lumbriculus variegatus. Studies were done on complete worms ("feeding") and worms where the head was absent ("nonfeeding") using (14) C-labeled ingredients. Biota sediment accumulation factors (BSAF), based on uptake of (14) C, for feeding worms increased in the order fluoxetine (0.3) < diclofenac (0.5) < triclosan (9), which is correlated with a corresponding increase in log octanol-water partition coefficient. Biota sediment accumulation factor estimates are representative of maximum values because the degree of biotransformation in the worms was not quantified. Although no significant differences were seen between the uptake of diclofenac and that of fluoxetine in feeding and nonfeeding worms, uptake of the more hydrophobic antimicrobial, triclosan, into the feeding worms was significantly greater than that in the nonfeeding worms, with the 48-h BSAF for feeding worms being 36% higher than that for the nonfeeding worms. The results imply that dietary uptake contributes to the uptake of triclosan, which may be a result of the high hydrophobicity of the compound. Models that estimate exposure of ionizable substances may need to consider uptake from both the water column and food, particularly when assessing risks from dynamic exposures to organic contaminants. © 2015 SETAC.

Role of ethnicity in human papillomavirus vaccination uptake: a cross-sectional study of girls from ethnic minority groups attending London schools.

PubMed

Rockliffe, Lauren; Waller, Jo; Marlow, Laura A V; Forster, Alice S

2017-02-23

Research suggests that girls from ethnic minority groups are less likely to receive the human papillomavirus (HPV) vaccination than white British girls; however, the specific ethnic minority groups that have lower uptake have not been identified. This study aimed to examine the relationship between school-level uptake and ethnicity as well as uptake and other ethnicity-related factors, to understand which specific groups are less likely to receive the vaccination. Aggregated uptake rates from 195 schools were obtained for each of the three recommended vaccine doses from 2008 to 2010. Census data at the lower super output area (LSOA) level for the postcode of each school were also obtained, describing the ethnic breakdown of the resident population (ethnicity, language spoken, religion, proficiency in English and duration of residency in the UK). These were used as proxy measures of the ethnic make-up of the schools. The most prevalent non-majority group for each ethnicity and ethnicity-related factor was assigned to each school. Analyses explored differences in uptake by ethnicity and ethnicity-related factors. No significant differences in vaccination uptake were found by ethnicity or ethnicity-related factors, although descriptive differences were apparent. Schools in areas where black ethnicities were the most prevalent non-white British ethnicities had consistently low rates of uptake for all doses. Schools in areas where some Asian ethnicities were the most prevalent non-white British ethnicities had consistently high rates of uptake for all doses. There was evidence of variability in mean uptake rates for ethnicities within 'black' and 'Asian' ethnic groups. Future research would benefit from focusing on specific ethnicities rather than broad ethnic categories. Replication of this study with a larger sample and using complete individual-level data, collected on a national level, would provide a clearer indication of where ethnic differences in HPV vaccination uptake exist. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

18F-FLT PET/CT in the Evaluation of Pheochromocytomas and Paragangliomas: A Pilot Study.

PubMed

Blanchet, Elise M; Taieb, David; Millo, Corina; Martucci, Victoria; Chen, Clara C; Merino, Maria; Herscovitch, Peter; Pacak, Karel

2015-12-01

(18)F-FDG PET/CT has been proven to be a highly sensitive method for pheochromocytomas/paragangliomas (PHEOs/PGLs) associated with succinate dehydrogenase (SDH) mutations. This finding has been attributed to altered tumor cell metabolism resulting from these mutations and does not provide additional prognostic information to genotype. Therefore, identification of new biomarkers for aggressiveness is needed. A high Ki-67 index was proposed to be an additional prognostic factor. This pilot study aimed to evaluate 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET/CT, a PET proliferation tracer, as a potential imaging agent in a series of 12 PHEO/PGL patients with different genetic backgrounds, to compare (18)F-FLT uptake with (18)F-FDG PET/CT, and to evaluate classic factors of aggressiveness. Twelve patients (7 metastatic and 5 nonmetastatic) were prospectively evaluated with (18)F-FDG and (18)F-FLT and followed for at least 2 y after the initial imaging work-up. Uptake was assessed at a lesion level, visually and quantitatively by maximum standardized uptake values (SUVmax) for both tracers. (18)F-FLT uptake was compared with risk factors known to be linked with a poor prognosis in PGLs (SDHB-mutated status, lesion size, dopaminergic phenotype) and with (18)F-FDG uptake. In 12 patients, 77 lesions were assessed. All lesions had low (18)F-FLT uptake (median SUVmax, 2.25; range, 0.7-4.5). There was no apparent superiority of (18)F-FLT uptake in progressive lesions, and most of the lesions showed a mismatch, with high (18)F-FDG uptake (median SUVmax, 10.8; range, 1.1-79.0) contrasting with low (18)F-FLT uptake. This study suggests that PHEOs/PGLs-even those that progress-do not exhibit intense (18)F-FLT uptake. It provides the first in vivo demonstration that proliferation may not be a major determinant of (18)F-FDG uptake in these tumors. These findings provide new insight into the biologic behavior of PGL and suggest that antiproliferative agents may be suboptimal for treatment of these tumors. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

64Cu-DOTATATE for Noninvasive Assessment of Atherosclerosis in Large Arteries and Its Correlation with Risk Factors: Head-to-Head Comparison with 68Ga-DOTATOC in 60 Patients.

PubMed

Malmberg, Catarina; Ripa, Rasmus S; Johnbeck, Camilla B; Knigge, Ulrich; Langer, Seppo W; Mortensen, Jann; Oturai, Peter; Loft, Annika; Hag, Anne Mette; Kjær, Andreas

2015-12-01

The somatostatin receptor subtype 2 is expressed on macrophages, an abundant cell type in the atherosclerotic plaque. Visualization of somatostatin receptor subtype 2, for oncologic purposes, is frequently made using the DOTA-derived somatostatin analogs DOTATOC or DOTATATE for PET. We aimed to compare the uptake of the PET tracers (68)Ga-DOTATOC and (64)Cu-DOTATATE in large arteries, in the assessment of atherosclerosis by noninvasive imaging technique, combining PET and CT. Further, the correlation of uptake and cardiovascular risk factors was investigated. Sixty consecutive patients with neuroendocrine tumors underwent both (68)Ga-DOTATOC and (64)Cu-DOTATATE PET/CT scans, in random order. For each scan, the maximum and mean standardized uptake values (SUVs) were calculated in 5 arterial segments. In addition, the blood-pool-corrected target-to-background ratio was calculated. Uptake of the tracers was correlated with cardiovascular risk factors collected from medical records. We found detectable uptake of both tracers in all arterial segments studied. Uptake of (64)Cu-DOTATATE was significantly higher than (68)Ga-DOTATOC in the vascular regions both when calculated as maximum and mean uptake. There was a significant association between Framingham risk score and the overall maximum uptake of (64)Cu-DOTATATE using SUV (r = 0.4; P = 0.004) as well as target-to-background ratio (r = 0.3; P = 0.04), whereas no association was found with (68)Ga-DOTATOC. The association of risk factors and maximum SUV of (64)Cu-DOTATATE was found driven by body mass index, smoking, diabetes, and coronary calcium score (P < 0.001, P = 0.01, P = 0.005, and P = 0.03, respectively). In a series of oncologic patients, vascular uptake of (68)Ga-DOTATOC and (64)Cu-DOTATATE was found, with highest uptake of the latter. Uptake of (64)Cu-DOTATATE, but not of (68)Ga-DOTATOC, was correlated with cardiovascular risk factors, suggesting a potential role for (64)Cu-DOTATATE in the assessment of atherosclerosis. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Mechanisms for the increase in phosphorus uptake of waterlogged plants: soil phosphorus availability, root morphology and uptake kinetics.

PubMed

Rubio, Gerardo; Oesterheld, Martín; Alvarez, Carina R; Lavado, Raúl S

1997-10-01

Waterlogging frequently reduces plant biomass allocation to roots. This response may result in a variety of alterations in mineral nutrition, which range from a proportional lowering of whole-plant nutrient concentration as a result of unchanged uptake per unit of root biomass, to a maintenance of nutrient concentration by means of an increase in uptake per unit of root biomass. The first objective of this paper was to test these two alternative hypothetical responses. In a pot experiment, we evaluated how plant P concentration of Paspalum dilatatum, (a waterlogging-tolerant grass from the Flooding Pampa, Argentina) was affected by waterlogging and P supply and how this related to changes in root-shoot ratio. Under both soil P levels waterlogging reduced root-shoot ratios, but did not reduce P concentration. Thus, uptake of P per unit of root biomass increased under waterlogging. Our second objective was to test three non-exclusive hypotheses about potential mechanisms for this increase in P uptake. We hypothesized that the greater P uptake per unit of root biomass was a consequence of: (1) an increase in soil P availability induced by waterlogging; (2) a change in root morphology, and/or (3) an increase in the intrinsic uptake capacity of each unit of root biomass. To test these hypotheses we evaluated (1) changes in P availability induced by waterlogging; (2) specific root length of waterlogged and control plants, and (3) P uptake kinetics in excised roots from waterlogged and control plants. The results supported the three hypotheses. Soil P avail-ability was higher during waterlogging periods, roots of waterlogged plants showed a morphology more favorable to nutrient uptake (finer roots) and these roots showed a higher physiological capacity to absorb P. The results suggest that both soil and plant mechanisms contributed to compensate, in terms of P nutrition, for the reduction in allocation to root growth. The rapid transformation of the P uptake system is likely an advantage for plants inhabiting frequently flooded environments with low P fertility, like the Flooding Pampa. This advantage would be one of the reasons for the increased relative abundance of P. dilatatum in the community after waterlogging periods.

Soil Methane uptake Model (MeMo): a process based model for global methane consumption by soils

NASA Astrophysics Data System (ADS)

Murguia-Flores, F.; Arndt, S.; Ganesan, A.; Hornibrook, E. R. C.; Murray-Tortarolo, G.

2016-12-01

Atmospheric methane (CH4) is a powerful greenhouse gas, responsible for 20% of global warming. The only terrestrial and biological sink is the uptake in the soils by methanotrophic bacteria, however there is large spatial and temporal heterogeneity in the magnitude of this sink. One way to provide a global understanding of this process is by using a mathematical model to simulate the mechanisms of the underlying physical and biological drivers. Here we present the soil Methane uptake Model (MeMo) a process-based model for the global methane consumption by soils. We have built on previous models by Ridgwell et al., (1999) and Curry et al., (2007), by making several advances. First, a general analytical solution of the one-dimensional diffusion-reaction equation was implemented that accounts for a maximum uptake depth and for a CH4 flux coming from below the surface (i.e. CH4 production in the soil). Secondly, we revisited and improved the effect of nitrogen inhibition, soil moisture and soil temperature on CH4 uptake in the light of newly available data and advances in our understanding of these drivers. Using observed forcing data, we estimated a global mean CH4 uptake of 31.2±1.2 Tg y-1 for the period 1990-2009 with an increasing trend of 0.1 Tg y-2. Our model represented the latitudinal pattern of uptake shown by field observations, with the highest uptake per unit area occurring over dry tropical forest and the lowest uptake in the polar desert. The highest seasonality occurred in the Northern Hemisphere, showing that the main driver of variability in a given year is from a combination of temperature and soil moisture. Our model showed that CH4 uptake is reduced from previous studies by approximately 10% at the regions with the highest nitrogen deposition: East Asia and Europe. Finally, our results suggest that more field measurements are needed to improve the modelling of the process, such as the basal oxidation rate for different ecosystems, the Q10 temperature response across different conditions and long term field CH4 uptake records.

Effects of genetic polymorphisms on the OCT1 and OCT2-mediated uptake of ranitidine.

PubMed

Meyer, Marleen Julia; Seitz, Tina; Brockmöller, Jürgen; Tzvetkov, Mladen Vassilev

2017-01-01

Ranitidine (Zantac®) is a H2-receptor antagonist commonly used for the treatment of acid-related gastrointestinal diseases. Ranitidine was reported to be a substrate of the organic cation transporters OCT1 and OCT2. The hepatic transporter OCT1 is highly genetically variable. Twelve major alleles confer partial or complete loss of OCT1 activity. The effects of these polymorphisms are highly substrate-specific and therefore difficult to predict. The renal transporter OCT2 has a common polymorphism, Ala270Ser, which was reported to affect OCT2 activity. In this study we analyzed the effects of genetic polymorphisms in OCT1 and OCT2 on the uptake of ranitidine and on its potency to inhibit uptake of other drugs. We characterized ranitidine uptake using HEK293 and CHO cells stably transfected to overexpress wild type OCT1, OCT2, or their naturally occurring allelic variants. Ranitidine was transported by wild-type OCT1 with a Km of 62.9 μM and a vmax of 1125 pmol/min/mg protein. Alleles OCT1*5, *6, *12, and *13 completely lacked ranitidine uptake. Alleles OCT1*2, *3, *4, and *10 had vmax values decreased by more than 50%. In contrast, OCT1*8 showed an increase of vmax by 25%. The effects of OCT1 alleles on ranitidine uptake strongly correlated with the effects on morphine uptake suggesting common interaction mechanisms of both drugs with OCT1. Ranitidine inhibited the OCT1-mediated uptake of metformin and morphine at clinically relevant concentrations. The inhibitory potency for morphine uptake was affected by the OCT1*2 allele. OCT2 showed only a limited uptake of ranitidine that was not significantly affected by the Ala270Ser polymorphism. We confirmed ranitidine as an OCT1 substrate and demonstrated that common genetic polymorphisms in OCT1 strongly affect ranitidine uptake and modulate ranitidine's potential to cause drug-drug interactions. The effects of the frequent OCT1 polymorphisms on ranitidine pharmacokinetics in humans remain to be analyzed.

Effects of genetic polymorphisms on the OCT1 and OCT2-mediated uptake of ranitidine

PubMed Central

Meyer, Marleen Julia; Seitz, Tina; Brockmöller, Jürgen

2017-01-01

Background Ranitidine (Zantac®) is a H2-receptor antagonist commonly used for the treatment of acid-related gastrointestinal diseases. Ranitidine was reported to be a substrate of the organic cation transporters OCT1 and OCT2. The hepatic transporter OCT1 is highly genetically variable. Twelve major alleles confer partial or complete loss of OCT1 activity. The effects of these polymorphisms are highly substrate-specific and therefore difficult to predict. The renal transporter OCT2 has a common polymorphism, Ala270Ser, which was reported to affect OCT2 activity. Aim In this study we analyzed the effects of genetic polymorphisms in OCT1 and OCT2 on the uptake of ranitidine and on its potency to inhibit uptake of other drugs. Methods and results We characterized ranitidine uptake using HEK293 and CHO cells stably transfected to overexpress wild type OCT1, OCT2, or their naturally occurring allelic variants. Ranitidine was transported by wild-type OCT1 with a Km of 62.9 μM and a vmax of 1125 pmol/min/mg protein. Alleles OCT1*5, *6, *12, and *13 completely lacked ranitidine uptake. Alleles OCT1*2, *3, *4, and *10 had vmax values decreased by more than 50%. In contrast, OCT1*8 showed an increase of vmax by 25%. The effects of OCT1 alleles on ranitidine uptake strongly correlated with the effects on morphine uptake suggesting common interaction mechanisms of both drugs with OCT1. Ranitidine inhibited the OCT1-mediated uptake of metformin and morphine at clinically relevant concentrations. The inhibitory potency for morphine uptake was affected by the OCT1*2 allele. OCT2 showed only a limited uptake of ranitidine that was not significantly affected by the Ala270Ser polymorphism. Conclusions We confirmed ranitidine as an OCT1 substrate and demonstrated that common genetic polymorphisms in OCT1 strongly affect ranitidine uptake and modulate ranitidine’s potential to cause drug-drug interactions. The effects of the frequent OCT1 polymorphisms on ranitidine pharmacokinetics in humans remain to be analyzed. PMID:29236753

Muscle contraction increases carnitine uptake via translocation of OCTN2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furuichi, Yasuro; Sugiura, Tomoko; Kato, Yukio

Highlights: Black-Right-Pointing-Pointer Muscle contraction augmented carnitine uptake into rat hindlimb muscles. Black-Right-Pointing-Pointer An increase in carnitine uptake was due to an intrinsic clearance, not blood flow. Black-Right-Pointing-Pointer Histochemical analysis showed sarcolemmal OCTN2 was emphasized after contraction. Black-Right-Pointing-Pointer OCTN2 protein in sarcolemmal fraction was increased in contracting muscles. -- Abstract: Since carnitine plays an important role in fat oxidation, influx of carnitine could be crucial for muscle metabolism. OCTN2 (SLC22A5), a sodium-dependent solute carrier, is assumed to transport carnitine into skeletal muscle cells. Acute regulation of OCTN2 activity in rat hindlimb muscles was investigated in response to electrically induced contractile activity.more » The tissue uptake clearance (CL{sub uptake}) of L-[{sup 3}H]carnitine during muscle contraction was examined in vivo using integration plot analysis. The CL{sub uptake} of [{sup 14}C]iodoantipyrine (IAP) was also determined as an index of tissue blood flow. To test the hypothesis that increased carnitine uptake involves the translocation of OCTN2, contraction-induced alteration in the subcellular localization of OCTN2 was examined. The CL{sub uptake} of L-[{sup 3}H]carnitine in the contracting muscles increased 1.4-1.7-fold as compared to that in the contralateral resting muscles (p < 0.05). The CL{sub uptake} of [{sup 14}C]IAP was much higher than that of L-[{sup 3}H]carnitine, but no association between the increase in carnitine uptake and blood flow was obtained. Co-immunostaining of OCTN2 and dystrophin (a muscle plasma membrane marker) showed an increase in OCTN2 signal in the plasma membrane after muscle contraction. Western blotting showed that the level of sarcolemmal OCTN2 was greater in contracting muscles than in resting muscles (p < 0.05). The present study showed that muscle contraction facilitated carnitine uptake in skeletal muscles, possibly via the contraction-induced translocation of its specific transporter OCTN2 to the plasma membrane.« less

Uptake coefficients for biosolids-amended dryland winter wheat

USDA-ARS?s Scientific Manuscript database

Biosolids regulations developed in the United States employed risk assessment impacts of trace element additions on plant uptake. The US Environmental Protection Agency adapted the uptake coefficient (ratio of plant concentration to quantity of element added) when developing limitations on selected...

Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation,

EPA Science Inventory

Objectives. This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Approach/Activities. Fifty-five studies were found where both passive sampler uptake...

β2-Adrenoceptors and non-β-adrenoceptors mediate effects of BRL37344 and clenbuterol on glucose uptake in soleus muscle: studies using knockout mice

PubMed Central

Ngala, Robert A; O'Dowd, Jacqueline; Wang, Steven J; Stocker, Claire; Cawthorne, Michael A; Arch, Jonathan RS

2009-01-01

Background and purpose: In previous work, 10 pM BRL37344 and 10 pM clenbuterol stimulated glucose uptake in mouse soleus muscle. Ten nM BRL37344 also stimulated uptake but 100 nM clenbuterol inhibited uptake. Antagonist studies suggested that the opposite effects of 10 nM BRL37344 and 100 nM clenbuterol are mediated by the β2-adrenoceptor. BRL37344 and clenbuterol have been studied in muscles that lack β3-, β2- or all three β-adrenoceptors. Effects of β-adrenoceptor antagonists on responses to the agonists have been studied further using muscles from wild-type mice. Experimental approach: Soleus muscles of wild-type or β-adrenoceptor knockout mice were incubated with 2-deoxy[1-14C]-glucose, and β-adrenoceptor ligands. Formation of 2-deoxy[1-14C]-glucose-6-phosphate was measured. Key results: Concentration–response relationships were similar for BRL37344 and clenbuterol in normal muscle and muscle lacking β3-adrenoceptors. Ten pM BRL37344 and clenbuterol stimulated glucose uptake in muscle lacking β2-adrenoceptors or all three β-adrenoceptors, but 10 nM BRL37344 did not stimulate uptake in either case, and 100 nM clenbuterol stimulated, rather than inhibited, uptake in muscle lacking β2-adrenoceptors. One hundred nM clenbuterol also stimulated glucose uptake in normal muscle when β2-adrenoceptors were blocked with ICI118551, and this was not prevented by antagonism of β1- or β3-adrenoceptors. Conclusions and implications: Ten nM BRL37344 and 100 nM clenbuterol have opposite effects on glucose uptake but both effects are mediated by the β2-adrenoceptor – apparently an example of agonist-directed signalling. Ten pM BRL37344, 10 pM clenbuterol and 100 nM clenbuterol in the presence of ICI118551 stimulate glucose uptake via β-adrenoceptor-independent mechanisms, demonstrating unknown properties for the agonists. PMID:19912225

AMPKα2 deficiency uncovers time dependency in the regulation of contraction-induced palmitate and glucose uptake in mouse muscle.

PubMed

Abbott, Marcia J; Bogachus, Lindsey D; Turcotte, Lorraine P

2011-07-01

AMP-activated protein kinase (AMPK) is a fuel sensor in skeletal muscle with multiple downstream signaling targets that may be triggered by increases in intracellular Ca(2+) concentration ([Ca(2+)]). The purpose of this study was to determine whether increases in intracellular [Ca(2+)] induced by caffeine act solely via AMPKα(2) and whether AMPKα(2) is essential to increase glucose uptake, fatty acid (FA) uptake, and FA oxidation in contracting skeletal muscle. Hindlimbs from wild-type (WT) or AMPKα(2) dominant-negative (DN) transgene mice were perfused during rest (n = 11), treatment with 3 mM caffeine (n = 10), or muscle contraction (n = 11). Time-dependent effects on glucose and FA uptake were uncovered throughout the 20-min muscle contraction perfusion period (P < 0.05). Glucose uptake rates did not increase in DN mice during muscle contraction until the last 5 min of the protocol (P < 0.05). FA uptake rates were elevated at the onset of muscle contraction and diminished by the end of the protocol in DN mice (P < 0.05). FA oxidation rates were abolished in the DN mice during muscle contraction (P < 0.05). The DN transgene had no effect on caffeine-induced FA uptake and oxidation (P > 0.05). Glucose uptake rates were blunted in caffeine-treated DN mice (P < 0.05). The DN transgene resulted in a greater use of intramuscular triglycerides as a fuel source during muscle contraction. The DN transgene did not alter caffeine- or contraction-mediated changes in the phosphorylation of Ca(2+)/calmodulin-dependent protein kinase I or ERK1/2 (P > 0.05). These data suggest that AMPKα(2) is involved in the regulation of substrate uptake in a time-dependent manner in contracting muscle but is not necessary for regulation of FA uptake and oxidation during caffeine treatment.

[Effects of soil pH on the competitive uptake of amino acids by maize and microorganisms].

PubMed

Ma, Qing Xu; Wang, Jun; Cao, Xiao Chuang; Sun, Yan; Sun, Tao; Wu, Liang Huan

2017-07-18

Organic nitrogen can play an important role in plant growth, and soil pH changed greatly due to the over-use of chemical fertilizers, but the effects of soil pH on the competitive uptake of amino acids by plants and rhizosphere microorganisms are lack of detailed research. To study the effects of soil pH on the uptake of amino acids by maize and soil microorganisms, two soils from Hangzhou and Tieling were selected, and the soil pH was changed by the electrokinesis, then the 15 N-labeled glycine was injected to the centrifuge tube with a short-term uptake of 4 h. Soil pH had a significant effect on the shoot and root biomass, and the optimal pH for maize shoot growth was 6.48 for Hangzhou red soil, while it was 7.65 for Tieling brown soil. For Hangzhou soil, the 15 N abundance of maize shoots under pH=6.48 was significantly higher than under other treatments, and the uptake amount of 15 N-glycine was also much higher. However, the 15 N abundance of maize shoots and roots under pH=7.65 Tieling soil was significantly lower than it under pH=5.78, but the uptake amount of 15 N-glycine under pH=7.65 was much higher. The microbial biomass C was much higher in pH=6.48 Hangzhou soil, while it was much lower in pH=7.65 Tieling soil. According to the results of root uptake, root to shoot transportation, and the competition with microorganisms, we suggested that although facing the fierce competition with microorganisms, the maize grown in pH=6.48 Hangzhou soil increased the uptake of glycine by increasing its root uptake and root to shoot transportation. While in pH=7.65 Tieling soil, the activity of microorganisms was decreased, which decreased the competition with maize for glycine, and increased the uptake of glycine by maize.

Can frequent precipitation moderate drought impact on peatmoss carbon uptake in northern peatlands?

NASA Astrophysics Data System (ADS)

Nijp, Jelmer; Limpens, Juul; Metselaar, Klaas; van der Zee, Sjoerd; Berendse, Frank; Robroek, Bjorn

2014-05-01

Northern peatlands represent one of the largest global carbon stores that can potentially be released by water table drawdown during extreme summer droughts. Small precipitation events may moderate negative impacts of deep water levels on carbon uptake by sustaining photosynthesis of peatmoss (Sphagnum spp.), the key species in these ecosystems. We experimentally assessed the importance of the temporal distribution of precipitation for Sphagnum water supply and carbon uptake during a stepwise decrease in water levels in a growth chamber. CO2 exchange and the water balance were measured for intact cores of three peatmoss species representative of three contrasting habitats in northern peatlands (Sphagnum fuscum, S. balticum and S. majus). For shallow water levels, capillary rise was the most important source of water for peatmoss photosynthesis and precipitation did not promote carbon uptake irrespective of peatmoss species. For deep water levels, however, precipitation dominated over capillary rise and moderated adverse effects of drought on carbon uptake by peat mosses. The ability to use the transient water supply by precipitation was species-specific: carbon uptake of S. fuscum increased linearly with precipitation frequency for deep water levels, whereas S. balticum and S. majus showed depressed carbon uptake at intermediate precipitation frequencies. Our results highlight the importance of precipitation for carbon uptake by peatmosses. The potential of precipitation to moderate drought impact, however, is species specific and depends on the temporal distribution of precipitation and water level. These results also suggest that modelling approaches in which water level depth is used as the only state variable determining water availability in the living moss layer and (in)directly linked to Sphagnum carbon uptake may have serious drawbacks. The predictive power of peatland ecosystem models may be reduced when deep water levels prevail, as precipitation frequency and quantity are likely the main variables controlling carbon uptake.

Psychological factors associated with uptake of the childhood influenza vaccine and perception of post-vaccination side-effects: A cross-sectional survey in England.

PubMed

Smith, Louise E; Webster, Rebecca K; Weinman, John; Amlôt, Richard; Yiend, Jenny; Rubin, G James

2017-04-04

To identify predictors of: uptake of the childhood influenza vaccine in the 2015-2016 influenza season, parental perceptions of side-effects from the influenza vaccine and intention to vaccinate one's child for influenza in the 2016-2017 influenza season. Cross-sectional online survey. Data were collected in England shortly after the end of the 2015-2016 immunization campaign. 1001 parents or guardians of children aged between two and seven. Self-reported uptake of the childhood influenza vaccine in the 2015-2016 influenza season, perception of side-effects from the influenza vaccine and intention to vaccinate one's child in the 2016-2017 influenza season. Self-reported uptake of the childhood influenza vaccine was 52.8%. Factors strongly positively associated with uptake included the child having previously been vaccinated against influenza, perceiving the vaccine to be effective and perceiving the child to be susceptible to flu. Factors strongly negatively associated with uptake included perceiving the vaccine to be unsafe, to cause short-term side-effects or long-term health problems and believing that yearly vaccination may overload the immune system. Predictors of intended vaccine uptake in 2016-2017 were similar. Participants who perceived side-effects after the 2015-2016 vaccination reported being less likely to vaccinate their child next year. Side-effects were more likely to be reported in first-born children, by participants who knew another child who had side-effects, those who thought that the vaccine would interact with medication that the child was currently taking, and those who believed the vaccine causes short-term side-effects. Perceptions about the childhood influenza vaccine show strong associations with uptake, intended uptake and perception of side-effects. Attempts to improve uptake rates from their current low levels must address these perceptions. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Prognostic value of the oxygen uptake efficiency slope and other exercise variables in patients with coronary artery disease.

PubMed

Coeckelberghs, Ellen; Buys, Roselien; Goetschalckx, Kaatje; Cornelissen, Véronique A; Vanhees, Luc

2016-02-01

Peak exercise capacity is an independent predictor for mortality in patients with coronary artery disease. However, sometimes cardiopulmonary exercise tests are stopped prematurely. Therefore, submaximal exercise measures such as the oxygen uptake efficiency slope have been introduced. The aim of this study was to assess the prognostic value of the oxygen uptake efficiency slope and other exercise parameters, in patients with coronary artery disease. Between 2000 and 2011, 1409 patients with coronary artery disease (age 60.7 ± 9.9 years; 1205 males) underwent cardiopulmonary exercise tests. A maximal effort was not reached in 161 (11.5%) patients. The oxygen uptake efficiency slope was calculated and information on mortality was obtained. Cox proportional hazards regression analyses were used to assess the relation of oxygen uptake efficiency slope and other gas exchange variables with all-cause and cardiovascular mortality. Receiver operating characteristic curve analyses was performed to define optimal cut-off values. During an average follow-up of 7.45 ± 3.20 years (range 0.16-13.95 years), 158 patients died, among which 68 patients for cardiovascular reasons. The oxygen uptake efficiency slope was related to all-cause (hazard ratio: 0.568, p < 0.001) and cardiovascular (hazard ratio: 0.461, p < 0.001) mortality. When significant covariates were entered in the analysis, oxygen uptake efficiency slope remained related to mortality (p < 0.05). When other submaximal exercise parameters were added to the model, oxygen uptake efficiency slope and minute ventilation/carbon dioxide production slope also remained significantly related to mortality. The oxygen uptake efficiency slope is an independent predictor for all-cause and cardiovascular mortality in patients with coronary artery disease, irrespective of a truly maximal effort during cardiopulmonary exercise tests. Furthermore, the oxygen uptake efficiency slope provides prognostic information, complementary to the minute ventilation/carbon dioxide production slope and peak exercise capacity. © The European Society of Cardiology 2015.

Characterization of cadmium uptake in Lactobacillus plantarum and isolation of cadmium and manganese uptake mutants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Z.; Reiske, H.R.; Wilson, D.B.

1999-11-01

Two different Cd{sup 2+} uptake systems were identified in Lactobacillus plantarum. One is a high-affinity, high-velocity Mn{sup 2+} uptake system which also takes up Cd{sup 2+} and is induced by Mn{sup 2+} starvation. The calculated K{sub m} and V{sub max} are 0.26 {mu}M and 3.6 {mu}mol g of dry cell{sup {minus}1} min{sup {minus}1}, respectively. Unlike Mn{sup 2+} uptake, which is facilitated by citrate and related tricarboxylic acids, Cd{sup 2+} uptake is weakly inhibited by citrate. Cd{sup 2+} and Mn{sup 2+} are competitive inhibitors of each other, and the affinity of the system for Cd{sup 2+} is higher than that formore » Mn{sup 2+}. The other Cd{sup 2+} uptake system is expressed in Mn{sup 2+}-sufficient cells, and no K{sub m} can be calculated for it because uptake is nonsaturable. Mn{sup 2+} does not compete for transport through this system, nor does any other tested cation, i.e., Zn{sup 2+}, Cu{sup 2+}, Co{sup 2+}, Mg{sup 2+}, Ca{sup 2+}, Fe{sup 2+}, or Ni{sup 2+}. Both systems require energy, since uncouplers completely inhibit their activities. Two Mn{sup 2+}-dependent L. plantarum mutants were isolated by chemical mutagenesis and ampicillin enrichment. They required more than 5,000 times as much Mn{sup 2+} for growth as the parental strain. Mn{sup 2+} starvation-induced Cd{sup 2+} uptake in both mutants was less than 5% the wild-type rate. The low level of long-term Mn{sup 2+} or Cd{sup 2+} accumulation by the mutant strains also shows that the mutations eliminate the high-affinity Mn{sup 2+} and Cd{sup 2+} uptake system.« less

Development of accelerated net nitrate uptake. [Zea mays L

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacKown, C.T.; McClure, P.R.

1988-05-01

Upon initial nitrate exposure, net nitrate uptake rates in roots of a wide variety of plants accelerate within 6 to 8 hours to substantially greater rates. Effects of solution nitrate concentrations and short pulses of nitrate ({le}1 hour) upon nitrate-induced acceleration of nitrate uptake in maize (Zea mays L.) were determined. Root cultures of dark-grown seedlings, grown without nitrate, were exposed to 250 micromolar nitrate for 0.25 to 1 hour or to various solution nitrate concentration (10-250 micromolar) for 1 hour before returning them to a nitrate-free solution. Net nitrate uptake rates were assayed at various periods following nitrate exposuremore » and compared to rates of roots grown either in the absence of nitrate (CaSO{sub 4}-grown) or with continuous nitrate for at least 20 hours. Three hours after initial nitrate exposure, nitrate pulse treatments increased nitrate uptake rates three- to four-fold compared to the rates of CaSO{sub 4}-grown roots. When cycloheximide (5 micrograms per milliliter) was included during a 1-hour pulse with 250 micromolar nitrate, development of the accelerated nitrate uptake state was delayed. Otherwise, nitrate uptake rates reached maximum values within 6 hours before declining. Maximum rates, however, were significantly less than those of roots exposed continuously for 20, 32, or 44 hours. Pulsing for only 0.25 hour with 250 micromolar nitrate and for 1 hour with 10 micromolar caused acceleration of nitrate uptake, but the rates attained were either less than or not sustained for a duration comparable to those of roots pulsed for 1 hour with 250 micromolar nitrate. These results indicate that substantial development of nitrate-induced accelerated nitrate uptake state can be achieved by small endogenous accumulations of nitrate, which appear to moderate the activity or level of root nitrate uptake.« less

Social disparities in access to breast and cervical cancer screening by women living in Spain.

PubMed

Ricardo-Rodrigues, I; Jiménez-García, R; Hernández-Barrera, V; Carrasco-Garrido, P; Jiménez-Trujillo, I; López de Andrés, A

2015-07-01

To describe uptake of breast and cervical cancer screening by women living in Spain, analyse the possible associated social and health factors, and compare uptake rates with those obtained in previous surveys. Cross-sectional study using data from the 2011 Spanish national health survey. Uptake of breast cancer screening was analysed by asking women aged 40-69 years whether they had undergone mammography in the previous two years. Uptake of cervical cancer screening was analysed by asking women aged 25-65 years whether they had undergone cervical cytology in the previous three years. Independent variables included sociodemographic characteristics, and variables related to health status and lifestyle. Seventy-two percent of women had undergone mammography in the previous two years. Having private health insurance increased the probability of breast screening uptake four-fold [odds ratio (OR) 3.96, 95% confidence interval (CI) 2.71-5.79], and being an immigrant was a negative predictor for breast screening uptake. Seventy percent of women had undergone cervical cytology in the previous three years. Higher-educated women were more likely to have undergone cervical cancer screening (OR 2.59, 95% CI 1.97-3.40), and obese women and women living in rural areas were less likely to have undergone cervical cancer screening. There have been no relevant improvements in uptake rates of either breast or cervical cancer screening since 2006. Uptake of breast and cervical cancer screening could be improved in Spain, and uptake rates have stagnated over recent years. Social disparities have been detected with regard to access to these screening tests, indicating that it is necessary to continue researching and optimizing prevention programmes in order to improve uptake and reduce these disparities. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Comparison of Different Risk Perception Measures in Predicting Seasonal Influenza Vaccination among Healthy Chinese Adults in Hong Kong: A Prospective Longitudinal Study

PubMed Central

Liao, Qiuyan; Wong, Wing Sze; Fielding, Richard

2013-01-01

Background Risk perception is a reported predictor of vaccination uptake, but which measures of risk perception best predict influenza vaccination uptake remain unclear. Methodology During the main influenza seasons (between January and March) of 2009 (Wave 1) and 2010 (Wave 2),505 Chinese students and employees from a Hong Kong university completed an online survey. Multivariate logistic regression models were conducted to assess how well different risk perceptions measures in Wave 1 predicted vaccination uptake against seasonal influenza in Wave 2. Principal Findings The results of the multivariate logistic regression models showed that feeling at risk (β = 0.25, p = 0.021) was the better predictor compared with probability judgment while probability judgment (β = 0.25, p = 0.029 ) was better than beliefs about risk in predicting subsequent influenza vaccination uptake. Beliefs about risk and feeling at risk seemed to predict the same aspect of subsequent vaccination uptake because their associations with vaccination uptake became insignificant when paired into the logistic regression model. Similarly, to compare the four scales for assessing probability judgment in predicting vaccination uptake, the 7-point verbal scale remained a significant and stronger predictor for vaccination uptake when paired with other three scales; the 6-point verbal scale was a significant and stronger predictor when paired with the percentage scale or the 2-point verbal scale; and the percentage scale was a significant and stronger predictor only when paired with the 2-point verbal scale. Conclusions/Significance Beliefs about risk and feeling at risk are not well differentiated by Hong Kong Chinese people. Feeling at risk, an affective-cognitive dimension of risk perception predicts subsequent vaccination uptake better than do probability judgments. Among the four scales for assessing risk probability judgment, the 7-point verbal scale offered the best predictive power for subsequent vaccination uptake. PMID:23894292

Comparison of different risk perception measures in predicting seasonal influenza vaccination among healthy Chinese adults in Hong Kong: a prospective longitudinal study.

PubMed

Liao, Qiuyan; Wong, Wing Sze; Fielding, Richard

2013-01-01

Risk perception is a reported predictor of vaccination uptake, but which measures of risk perception best predict influenza vaccination uptake remain unclear. During the main influenza seasons (between January and March) of 2009 (Wave 1) and 2010 (Wave 2),505 Chinese students and employees from a Hong Kong university completed an online survey. Multivariate logistic regression models were conducted to assess how well different risk perceptions measures in Wave 1 predicted vaccination uptake against seasonal influenza in Wave 2. The results of the multivariate logistic regression models showed that feeling at risk (β = 0.25, p = 0.021) was the better predictor compared with probability judgment while probability judgment (β = 0.25, p = 0.029 ) was better than beliefs about risk in predicting subsequent influenza vaccination uptake. Beliefs about risk and feeling at risk seemed to predict the same aspect of subsequent vaccination uptake because their associations with vaccination uptake became insignificant when paired into the logistic regression model. Similarly, to compare the four scales for assessing probability judgment in predicting vaccination uptake, the 7-point verbal scale remained a significant and stronger predictor for vaccination uptake when paired with other three scales; the 6-point verbal scale was a significant and stronger predictor when paired with the percentage scale or the 2-point verbal scale; and the percentage scale was a significant and stronger predictor only when paired with the 2-point verbal scale. Beliefs about risk and feeling at risk are not well differentiated by Hong Kong Chinese people. Feeling at risk, an affective-cognitive dimension of risk perception predicts subsequent vaccination uptake better than do probability judgments. Among the four scales for assessing risk probability judgment, the 7-point verbal scale offered the best predictive power for subsequent vaccination uptake.

Sucrose uptake by pinocytosis in Amoeba proteus and the influence of external calcium

PubMed Central

1979-01-01

The relationship between Ca++ and pinocytosis was investigated in Amoeba proteus. Pinocytosis was induced with 0.01% alcian blue, a large molecular weight dye which binds irreversibly to the cell surface. The time-course and intensity of pinocytosis was monitored by following the uptake of [3H]SUCROSE. When the cells are exposed to 0.01% alcian blue, there is an immediate uptake of sucrose. The cells take up integral of 10% of their initial volume during the time-course of pinocytosis. The duration of pinocytosis in the amoeba is integral of 50 min, with maximum sucrose uptake occurring 15 min after the induction of pinocytosis. The pinocytotic uptake of sucrose is reversibly blocked at 3 degrees C and a decrease in pH increases the uptake of sucrose by pinocytosis. The process of pinocytosis is also dependent upon the concentration of the inducer in the external medium. The association between Ca++ and pinocytosis in A. proteus was investigated initially by determining the effect of the external Ca++ concentration on sucrose uptake induced by alcian blue. In Ca++-free medium, no sucrose uptake is observed in the presence of 0.01% alcian blue. As the Ca++ concentration is increased, up to a maximum of 0.1 mM, pinocytotic sucrose uptake is also increased. Increases in the external Ca++ concentration above 0.1 mM brings about a decrease in sucrose uptake. Further investigations into the association between Ca++ and pinocytosis demonstrated that the inducer of pinocytosis displaces surface calcium in the amoeba. It is suggested that Ca++ is involved in two separate stages in the process of pinocytosis; an initial displacement of surface calcium by the inducer which may increase the permeability of the membrane to solutes and a subsequent Ca++ influx bringing about localized increases in cytoplasmic Ca++ ion activity. PMID:512629

Reduced 123I-BMIPP uptake implies decreased myocardial flow reserve in patients with chronic stable angina.

PubMed

Kageyama, Hiroyuki; Morita, Koichi; Katoh, Chietsugu; Tsukamoto, Takahiro; Noriyasu, Kazuyuki; Mabuchi, Megumi; Naya, Masanao; Kawai, Yuko; Tamaki, Nagara

2006-01-01

Long-chain fatty acid (LCFA) is the main energy source for normal myocardium at rest, but in ischemic myocardium, the main energy substrate shifts from LCFA to glucose. 123I-BMIPP is a radiolabeled LCFA analog. In chronic stable angina without previous infarction, we suppose that reduced 123I-BMIPP uptake is related to the substrate shift in myocardium with decreased myocardial flow reserve (MFR). The purpose of this study was to relate 123I-BMIPP uptake to rest myocardial blood flow (MBF), hyperemic MBF, and MFR assessed with 15O-water positron emission tomography (PET). We enrolled 21 patients with chronic stable angina without previous infarction, all of whom underwent 123I-BMIPP single-photon emission computed tomography (SPECT) and 15O-water PET. The left ventricle was divided into 13 segments. In each segment, rest MBF and hyperemic MBF were measured by PET. 123I-BMIPP uptake was evaluated as follows: score 0=normal, 1=slightly decreased uptake, 2=moderately decreased uptake, 3=severely decreased uptake, and 4=complete defect. 123I-BMIPP uptake was compared with rest MBF, hyperemic MBF, and MFR. The numbers of segments with 123I-BMIPP scores 0, 1, 2, 3, and 4 were 178, 40, 25, 24, and 0, respectively. The rest MBFs for scores 0, 1, 2, and 3 were 0.93+/-0.25, 0.86+/-0.21, 0.97+/-0.30, and 0.99+/-0.37 ml/min/g, respectively. The hyperemic MBFs for scores 0, 1, 2, and 3 were 2.76+/-1.29, 1.84+/-0.74, 1.37+/-0.39, and 1.08+/-0.40 ml/min/g, respectively. The MFRs for scores 0, 1, 2, and 3 were 3.01+/-1.38, 2.20+/-0.95, 1.44+/-0.22, and 1.10+/-0.26, respectively. As 123I-BMIPP uptake declined, hyperemic MBF and MFR decreased. In chronic stable angina without previous infarction, reduced 123I-BMIPP uptake implies decreased MFR.

Metabolism and acetylation contribute to leucine-mediated inhibition of cardiac glucose uptake.

PubMed

Renguet, Edith; Ginion, Audrey; Gélinas, Roselle; Bultot, Laurent; Auquier, Julien; Robillard Frayne, Isabelle; Daneault, Caroline; Vanoverschelde, Jean-Louis; Des Rosiers, Christine; Hue, Louis; Horman, Sandrine; Beauloye, Christophe; Bertrand, Luc

2017-08-01

High plasma leucine levels strongly correlate with type 2 diabetes. Studies of muscle cells have suggested that leucine alters the insulin response for glucose transport by activating an insulin-negative feedback loop driven by the mammalian target of rapamycin/p70 ribosomal S6 kinase (mTOR/p70S6K) pathway. Here, we examined the molecular mechanism involved in leucine's action on cardiac glucose uptake. Leucine was indeed able to curb glucose uptake after insulin stimulation in both cultured cardiomyocytes and perfused hearts. Although leucine activated mTOR/p70S6K, the mTOR inhibitor rapamycin did not prevent leucine's inhibitory action on glucose uptake, ruling out the contribution of the insulin-negative feedback loop. α-Ketoisocaproate, the first metabolite of leucine catabolism, mimicked leucine's effect on glucose uptake. Incubation of cardiomyocytes with [ 13 C]leucine ascertained its metabolism to ketone bodies (KBs), which had a similar negative impact on insulin-stimulated glucose transport. Both leucine and KBs reduced glucose uptake by affecting translocation of glucose transporter 4 (GLUT4) to the plasma membrane. Finally, we found that leucine elevated the global protein acetylation level. Pharmacological inhibition of lysine acetyltransferases counteracted this increase in protein acetylation and prevented leucine's inhibitory action on both glucose uptake and GLUT4 translocation. Taken together, these results indicate that leucine metabolism into KBs contributes to inhibition of cardiac glucose uptake by hampering the translocation of GLUT4-containing vesicles via acetylation. They offer new insights into the establishment of insulin resistance in the heart. NEW & NOTEWORTHY Catabolism of the branched-chain amino acid leucine into ketone bodies efficiently inhibits cardiac glucose uptake through decreased translocation of glucose transporter 4 to the plasma membrane. Leucine increases protein acetylation. Pharmacological inhibition of acetylation reverses leucine's action, suggesting acetylation involvement in this phenomenon.Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/leucine-metabolism-inhibits-cardiac-glucose-uptake/. Copyright © 2017 the American Physiological Society.

Drier summers cancel out the CO2 uptake enhancement induced by warmer springs.

PubMed

Angert, A; Biraud, S; Bonfils, C; Henning, C C; Buermann, W; Pinzon, J; Tucker, C J; Fung, I

2005-08-02

An increase in photosynthetic activity of the northern hemisphere terrestrial vegetation, as derived from satellite observations, has been reported in previous studies. The amplitude of the seasonal cycle of the annually detrended atmospheric CO(2) in the northern hemisphere (an indicator of biospheric activity) also increased during that period. We found, by analyzing the annually detrended CO(2) record by season, that early summer (June) CO(2) concentrations indeed decreased from 1985 to 1991, and they have continued to decrease from 1994 up to 2002. This decrease indicates accelerating springtime net CO(2) uptake. However, the CO(2) minimum concentration in late summer (an indicator of net growing-season uptake) showed no positive trend since 1994, indicating that lower net CO(2) uptake during summer cancelled out the enhanced uptake during spring. Using a recent satellite normalized difference vegetation index data set and climate data, we show that this lower summer uptake is probably the result of hotter and drier summers in both mid and high latitudes, demonstrating that a warming climate does not necessarily lead to higher CO(2) growing-season uptake, even in high-latitude ecosystems that are considered to be temperature limited.

Ontogenesis of uptake and deamination of 5-hydroxytryptamine, dopamine and beta-phenylethylamine in isolated perfused lung and lung homogenates from rats.

PubMed Central

Ben-Harari, R. R.; Youdim, M. B.

1981-01-01

1. Uptake of 5-hydroxytryptamine (5-HT) and beta-phenylethylamine (PEA) was studied in perfused lung from male rats between 10 and 70 days old. 2. Monoamine oxidase (MAO) activity towards 5-HT, PEA and dopamine was studied in homogenate preparations of lung from rats aged between 5 and 80 days. 3. Uptake of 5-HT (10 microM) decreased throughout the age range studied but uptake of PEA (50 microM) increased for the first 30 days and beyond this age it decreased. Metabolites formed for both amines reflected the changes in uptake. 4. MAO activity deaminating 5-HT is well developed by day 10 and reaches its maximum by day 40. For dopamine and PEA, MAO activity remained low until day 20, and the developed rapidly, reaching a maximum by day 40 for dopamine; activity towards PEA did not reach a maximum by day 80. 5. These results show that uptake and MAO activity changes with age and thus the lung responds like other tissues. 6. These results also demonstrate the independent development of uptake and MAO activity towards 5-HT, PEA and dopamine. PMID:7284689

[Kinetics of uptake of phosphates and nitrates by marine multicellular algae Gelidium latifolium (Grev.) Born. et Thur].

PubMed

Silkin, V A; Chubchikova, I N

2007-01-01

We studied nonstationary kinetics of the uptake of phosphates and nitrates by the red marine algae Gelidium latifolium (Grev.) Born et Thur. and calculated constants of the Michaelis-Menten equation for these elements. In the area of 0-3 microM, the kinetics of phosphate consumption had the following coefficients: maximum rate of uptake 0.8 micromol/(g x h), constant of half-saturation 1.745 microM. For nitrate nitrogen at 0-30 microM, an adaptive strategy of uptake kinetics was noted with change of the equation parameters with time: after 1 h, the maximum rate of uptake was 5.1 micromol/(g x h) and constant of half-saturation 19 gM, while within 2 h, the maximum rate of uptake significantly increased. This could be related to the synthesis of nitrate reductase. Coupled with the uptake of nitrates, nonstationary kinetics of the release of nitrates in the surrounding medium had a one-peak pattern: the maximum concentration of nitrites in the medium and the time of its achievement increased with the initial concentration of nitrates. The maximum concentration of nitrites was 6 to 14% of the initial concentration in the medium.

Regional cerebral (18)FDG uptake during subarachnoid hemorrhage induced vasospasm.

PubMed

Novak, Laszlo; Emri, Miklos; Molnar, Peter; Balkay, Laszlo; Szabo, Sandor; Rozsa, Laszlo; Lengyel, Zsolt; Tron, Lajos

2006-12-01

The aim was to elucidate whether aneurysmal subarachnoid hemorrhage (SAH)-induced vasospasm induces changes of regional glucose uptake in surgically treated, asymptomatic cases. (18)FDG uptake (standardized uptake value, SUV) was analysed with PET in eight surgically treated aneurismal patients with a mean middle cerebral artery flow velocity >120 cm/seconds measured with transcranial Doppler ultrasound. Data were compared with a healthy control group using Statistical Parametric Mapping (SPM99b). Six of the eight patients had no focal neurological signs. The inhomogeneous bilateral increase in SUV (p<0.0001) was asymmetrical, with an almost 70% larger volume on the operated side. Reduced glucose uptake was found in the frontal and temporobasal regions of the two patients with neurological deficits (p<0.0001); the affected volume was 40% larger on the operated side. SAH-induced vasospasm results in widespread increase of glucose uptake-probably reflecting increased glycolysis. This was earlier than neurological focal signs appear. Decreased glucose uptake can be detected in severe cases of vasospasm reflected by neurological deficit. Although the changes are more prominent where surgery had taken place our results suggest that not only the surgery, but also subarachnoid blood might have resulted in our findings.

HPV vaccination prevalence, parental barriers and motivators to vaccinating children in Hawai'i.

PubMed

Dela Cruz, May Rose Isnec; Braun, Kathryn L; Tsark, Jo Ann Umilani; Albright, Cheryl Lynn; Chen, John J

2018-05-10

To determine the prevalence and barriers to human papillomavirus (HPV) vaccine uptake among 11-18 year olds in the Hawai'i's four major ethnic groups-Native Hawaiians, Filipinos, Japanese, and Caucasians. A telephone survey assessed parents' knowledge of HPV and the HPV vaccine, status of their child's HPV vaccine uptake, variables operationalizing the Health Belief Model, and barriers and motivators to uptake. Across the groups, 799 parents completed the survey. About 35% of daughters and 19% of sons had received all three shots. Although ethnic differences in vaccine uptake were seen in bivariate analysis (with significantly lower uptake in Filipino youth), in multivariable logistic regression analysis, only Caucasian parents were significantly less likely to start their sons on the HPV vaccine series compared with Japanese parents (reference group). Having heard about the vaccine, believing in its effectiveness, and older age of the child were also associated with vaccine uptake. Motivators for HPV vaccination were physician's recommendation and wanting to protect one's child. The primary barrier to uptake was lack of knowledge about the vaccine. Findings reinforce the fact that a physician's recommendation and receipt of information about the vaccine are strong motivators for parents to vaccinate their children, regardless of ethnicity.

Foliar water uptake of Tamarix ramosissima from an atmosphere of high humidity.

PubMed

Li, Shuang; Xiao, Hong-lang; Zhao, Liang; Zhou, Mao-Xian; Wang, Fang

2014-01-01

Many species have been found to be capable of foliar water uptake, but little research has focused on this in desert plants. Tamarix ramosissima was investigated to determine whether its leaves can directly absorb water from high humidity atmosphere and, if they can, to understand the magnitude and importance of foliar water uptake. Various techniques were adopted to demonstrate foliar water uptake under submergence or high atmospheric humidity. The mean increase in leaf water content after submergence was 29.38% and 20.93% for mature and tender leaves, respectively. In the chamber experiment, obvious reverse sap flow occurred when relative humidity (RH) was persistently above 90%. Reverse flow was recorded first in twigs, then in branches and stems. For the stem, the percentage of negative sap flow rate accounting for the maximum value of sap flow reached 10.71%, and its amount accounted for 7.54% of diurnal sap flow. Small rainfall can not only compensate water loss of plant by foliar uptake, but also suppress transpiration. Foliar uptake can appear in the daytime under certain rainfall events. High atmospheric humidity is beneficial for enhancing the water status of plants. Foliar uptake should be an important strategy of water acquisition for desert plants.

The Effect of a Shear Flow on the Uptake of LDL and Ac-LDL by Cultured Vascular Endothelial Cells

NASA Astrophysics Data System (ADS)

Niwa, Koichi; Karino, Takeshi

The effects of a shear flow on the uptake of fluorescence-labeled low-density lipoprotein (DiI-LDL), acetylated LDL (DiI-Ac-LDL), and lucifer yellow (LY; a tracer of fluid-phase endocytosis) by cultured bovine aortic ECs were studied using a rotating-disk shearing apparatus. It was found that 2hours’ exposure of ECs to a laminar shear flow that imposed ECs an area-mean shear stress of 10dynes/cm2 caused an increase in the uptake of DiI-LDL and LY. By contrast, the uptake of DiI-Ac-LDL was decreased by exposure of the ECs to a shear flow. Addition of dextran sulfate (DS), a competitive inhibitor of scavenger receptors, reversed the effect of a shear flow on the uptake of DiI-Ac-LDL, resulting in an increase by the imposition of a shear flow, while the uptake of DiI-LDL and LY remained unaffected. It was concluded that a shear flow promotes the endocytosis of DiI-LDL and LY by ECs, but suppresses the uptake of DiI-Ac-LDL by ECs by inhibiting scavenger receptor-mediated endocytosis.

A longitudinal analysis of the effect of nonmedical exemption law and vaccine uptake on vaccine-targeted disease rates.

PubMed

Yang, Y Tony; Debold, Vicky

2014-02-01

We assessed how nonmedical exemption (NME) laws and annual uptake of vaccines required for school or daycare entry affect annual incidence rates for 5 vaccine-targeted diseases: pertussis, measles, mumps, Haemophilus influenzae type B, and hepatitis B. We employed longitudinal mixed-effects models to examine 2001-2008 vaccine-targeted disease data obtained from the National Notifiable Disease Surveillance System. Key explanatory variables were state-level vaccine-specific uptake rates from the National Immunization Survey and a state NME law restrictiveness level. NME law restrictiveness and vaccine uptake were not associated with disease incidence rate for hepatitis B, Haemophilus influenzae type B, measles, or mumps. Pertussis incidence rate, however, was negatively associated with NME law restrictiveness (b = -0.20; P = .03) and diphtheria-pertussis-tetanus vaccine uptake (b = -0.01; P = .05). State NME laws and vaccine uptake rates did not appear to influence lower-incidence diseases but may influence reported disease rates for higher-incidence diseases. If all states increased their NME law restrictiveness by 1 level and diphtheria-pertussis-tetanus uptake by 1%, national annual pertussis cases could decrease by 1.14% (171 cases) and 0.04% (5 cases), respectively.

Impact of pharmacist administration of influenza vaccines on uptake in Canada

PubMed Central

Buchan, Sarah A.; Rosella, Laura C.; Finkelstein, Michael; Juurlink, David; Isenor, Jennifer; Marra, Fawziah; Patel, Anik; Russell, Margaret L.; Quach, Susan; Waite, Nancy; Kwong, Jeffrey C.

2017-01-01

BACKGROUND: Uptake of influenza vaccination in Canada remains suboptimal despite widespread public funding. To increase access, several provinces have implemented policies permitting pharmacists to administer influenza vaccines in community pharmacies. We examined the impact of such policies on the uptake of seasonal influenza vaccination in Canada. METHODS: We pooled data from the 2007–2014 cycles of the Canadian Community Health Survey (n = 481 526). To determine the impact of influenza vaccine administration by pharmacists, we estimated the prevalence ratio for the association between the presence of a pharmacist policy and individual-level vaccine uptake using a modified Poisson regression model (dependent variable: vaccine uptake) with normalized weights while controlling for numerous health and sociodemographic factors. RESULTS: Across all survey cycles combined, 28.8% of respondents reported receiving a seasonal influenza vaccine during the 12 months before survey participation. Introduction of a policy for pharmacist administration of influenza vaccine was associated with a modest increase in coverage (2.2%) and an individual’s likelihood of uptake (adjusted prevalence ratio 1.05, 95% confidence interval 1.02–1.08). INTERPRETATION: Uptake of influenza immunization was modestly increased in Canadian jurisdictions that allowed pharmacists to administer influenza vaccines. PMID:27503864

Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast.

PubMed

Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D; Andersen, Tonni G; Pomorski, Thomas G

2014-12-01

Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S. cerevisiae requires the presence of serum or albumin for efficient cholesterol uptake. These results suggest that albumin can serve as sterol donor in ABC transporter-dependent sterol uptake, a process potentially important for growth of C. glabrata inside infected humans. © 2014 The Authors. FEMS Yeast Research published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

High-affinity K+ uptake in pepper plants.

PubMed

Martínez-Cordero, M Angeles; Martínez, Vicente; Rubio, Francisco

2005-06-01

High-affinity K+ uptake is an essential process for plant nutrition under K+-limiting conditions. The results presented here demonstrate that pepper (Capsicum annuum) plants grown in the absence of NH4+ and starved of K+ show an NH4+-sensitive high-affinity K+ uptake that allows plant roots to deplete external K+ to values below 1 microM. When plants are grown in the presence of NH4+, high-affinity K+ uptake is not inhibited by NH4+. Although NH4+-grown plants deplete external K+ below 1 microM in the absence of NH4+, when 1 mM NH4+ is present they do not deplete external K+ below 10 microM. A K+ transporter of the HAK family, CaHAK1, is very likely mediating the NH4+-sensitive component of the high-affinity K+ uptake in pepper roots. CaHAK1 is strongly induced in the roots that show the NH4+-sensitive high-affinity K+ uptake and its induction is reduced in K+-starved plants grown in the presence of NH4+. The NH4+-insensitive K+ uptake may be mediated by an AKT1-like K+ channel.

Moisture uptake of polyoxyethylene glycol glycerides used as matrices for drug delivery: kinetic modelling and practical implications.

PubMed

Qi, Sheng; Belton, Peter; McAuley, William; Codoni, Doroty; Darji, Neerav

2013-04-01

Gelucire 50/13, a polyoxyethylene glycol glyceride mixture, has been widely used in drug delivery, but its moisture uptake behaviour is still poorly understood. In this study, the effects of relative humidity, temperature, and drug incorporation on the moisture uptake of Gelucire are reported in relation to their practical implications for preparation of solid dispersions using this material. DVS combined with kinetics modelling was used as the main experimental method to study the moisture uptake behaviour of Gelucire. Thermal and microscopic methods were employed to investigate the effect of moisture uptake on the physical properties of the material and drug loaded solid dispersions. The moisture uptake by Gelucire 50/13 is temperature and relative humidity dependent. At low temperatures and low relative humidities, moisture sorption follows a GAB model. The model fitting indicated that at high relative humidities the sorption is a complex process, potentially involving PEG being dissolved and the PEG solution acting as solvent to dissolve other components. Careful control of the storage and processing environmental conditions are required when using Gelucire 50/13. The incorporation of model drugs not only influences the moisture uptake capacity of Gelucire 50/13 but also the solidification behaviour.

Light intensity affects the uptake and metabolism of glycine by pakchoi (Brassica chinensis L.)

NASA Astrophysics Data System (ADS)

Ma, Qingxu; Cao, Xiaochuang; Wu, Lianghuan; Mi, Wenhai; Feng, Ying

2016-02-01

The uptake of glycine by pakchoi (Brassica chinensis L.), when supplied as single N-source or in a mixture of glycine and inorganic N, was studied at different light intensities under sterile conditions. At the optimal intensity (414 μmol m-2 s-1) for plant growth, glycine, nitrate, and ammonium contributed 29.4%, 39.5%, and 31.1% shoot N, respectively, and light intensity altered the preferential absorption of N sources. The lower 15N-nitrate in root but higher in shoot and the higher 15N-glycine in root but lower in shoot suggested that most 15N-nitrate uptake by root transported to shoot rapidly, with the shoot being important for nitrate assimilation, and the N contribution of glycine was limited by post-uptake metabolism. The amount of glycine that was taken up by the plant was likely limited by root uptake at low light intensities and by the metabolism of ammonium produced by glycine at high light intensities. These results indicate that pakchoi has the ability to uptake a large quantity of glycine, but that uptake is strongly regulated by light intensity, with metabolism in the root inhibiting its N contribution.

Radioluminescence Microscopy: Measuring the Heterogeneous Uptake of Radiotracers in Single Living Cells

PubMed Central

Pratx, Guillem; Chen, Kai; Sun, Conroy; Martin, Lynn; Carpenter, Colin M.; Olcott, Peter D.; Xing, Lei

2012-01-01

Radiotracers play an important role in interrogating molecular processes both in vitro and in vivo. However, current methods are limited to measuring average radiotracer uptake in large cell populations and, as a result, lack the ability to quantify cell-to-cell variations. Here we apply a new technique, termed radioluminescence microscopy, to visualize radiotracer uptake in single living cells, in a standard fluorescence microscopy environment. In this technique, live cells are cultured sparsely on a thin scintillator plate and incubated with a radiotracer. Light produced following beta decay is measured using a highly sensitive microscope. Radioluminescence microscopy revealed strong heterogeneity in the uptake of [18F]fluoro-deoxyglucose (FDG) in single cells, which was found consistent with fluorescence imaging of a glucose analog. We also verified that dynamic uptake of FDG in single cells followed the standard two-tissue compartmental model. Last, we transfected cells with a fusion PET/fluorescence reporter gene and found that uptake of FHBG (a PET radiotracer for transgene expression) coincided with expression of the fluorescent protein. Together, these results indicate that radioluminescence microscopy can visualize radiotracer uptake with single-cell resolution, which may find a use in the precise characterization of radiotracers. PMID:23056276

Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation..

EPA Science Inventory

This review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Fifty-four studies were found where both passive sampler uptake and organism bioaccumulation wer...

Evaluating the Relationship between Equilibrium Passive Sampler Uptake and Aquatic Organism Bioaccumulation

EPA Science Inventory

This Critcal Review evaluates passive sampler uptake of hydrophobic organic contaminants (HOCs) in water column and interstitial water exposures as a surrogate for organism bioaccumulation. Fifty-seven studies were found where both passive sampler uptake and organism bioaccumulat...

A molecular recognizing system of serotonin in rat fetal axonal growth cones: uptake and high affinity binding.

PubMed

Mercado, R; Hernández, J

1992-09-18

Axonal growth cone particles (AGCP) isolated from prenatal and postnatal rat brain had different high-affinity 5-HT uptake characteristics. In postnatal AGCP the uptake behaves as in the adult rat brain, while in the prenatal AGCP the uptake characteristics seem to be in a transitional stage. Also in prenatal AGCP we observed specific, high-affinity 5-HT binding sites. These results support the idea of an important role for 5-HT during axogenesis.

Osthole activates glucose uptake but blocks full activation in L929 fibroblast cells, and inhibits uptake in HCLE cells

PubMed Central

Alabi, Ola D.; Gunnink, Stephen M.; Kuiper, Benjamin D.; Kerk, Samuel A.; Braun, Emily; Louters, Larry L.

2016-01-01

Aims Osthole, a coumarin derivative, has been used in Chinese medicine and studies have suggested a potential use in treatment of diabetes and cancers. Therefore, we investigated the effects of osthole and other coumarins on GLUT1 activity in two cell lines that exclusively express GLUT1. Main Methods We measured the magnitude and time frame of the effects of osthole and related coumarins on glucose uptake in two cells lines; L929 fibroblast cells which have low GLUT1 expression levels and low basal glucose uptake and HCLE cells which have high GLUT1 concentrations and high basal uptake. We also explored the effects of these coumarins in combination with other GLUT1 activators. Key findings Osthole activates glucose uptake in L929 cells with a modest maximum 1.7-fold activation achieved by 50 µM with both activation and recovery occurring within minutes. However, osthole blocks full acute activation of glucose uptake by other, more robust activators. This behavior mimics the effects of other thiol reactive compounds and suggests that osthole is interacting with cysteine residues, possibly within GLUT1 itself. Coumarin, 7-hydroxycoumarin, and 7-methoxycoumarin, do not affect glucose uptake, which is consistent with the notion that the isoprenoid structure in osthole may be important to gain membrane access to GLUT1. In contrast to its effects in L929 cells, osthole inhibits basal glucose uptake in the more active HCLE cells. Significance The differential effects of osthole in L929 and HCLE cells indicated that regulation of GLUT1 varies, likely depending on its membrane concentration. PMID:24657891

Osthole activates glucose uptake but blocks full activation in L929 fibroblast cells, and inhibits uptake in HCLE cells.

PubMed

Alabi, Ola D; Gunnink, Stephen M; Kuiper, Benjamin D; Kerk, Samuel A; Braun, Emily; Louters, Larry L

2014-05-02

Osthole, a coumarin derivative, has been used in Chinese medicine and studies have suggested a potential use in treatment of diabetes and cancers. Therefore, we investigated the effects of osthole and other coumarins on GLUT1 activity in two cell lines that exclusively express GLUT1. We measured the magnitude and time frame of the effects of osthole and related coumarins on glucose uptake in two cells lines; L929 fibroblast cells which have low GLUT1 expression levels and low basal glucose uptake and HCLE cells which have high GLUT1 concentrations and high basal uptake. We also explored the effects of these coumarins in combination with other GLUT1 activators. Osthole activates glucose uptake in L929 cells with a modest maximum 1.7-fold activation achieved by 50 μM with both activation and recovery occurring within minutes. However, osthole blocks full acute activation of glucose uptake by other, more robust activators. This behavior mimics the effects of other thiol reactive compounds and suggests that osthole is interacting with cysteine residues, possibly within GLUT1 itself. Coumarin, 7-hydroxycoumarin, and 7-methoxycoumarin, do not affect glucose uptake, which is consistent with the notion that the isoprenoid structure in osthole may be important to gain membrane access to GLUT1. In contrast to its effects in L929 cells, osthole inhibits basal glucose uptake in the more active HCLE cells. The differential effects of osthole in L929 and HCLE cells indicated that regulation of GLUT1 varies, likely depending on its membrane concentration. Copyright © 2014 Elsevier Inc. All rights reserved.

Glycerol uptake is by passive diffusion in the heart but by facilitated transport in RBCs at high glycerol levels in cold acclimated rainbow smelt (Osmerus mordax).

PubMed

Clow, Kathy A; Driedzic, William R

2012-04-15

Rainbow smelt (Osmerus mordax) is a small fish that accumulates glycerol at low winter seawater temperatures. In laboratory-held fish, glycerol concentration typically reaches 225 mM in plasma and in all cells. Glycerol uptake by the heart and red blood cells (RBCs) was assessed by tracking [(14)C(U)]glycerol into the acid-soluble pool. In fish acclimated to 9-10°C a decrease in perfusion/incubation temperature from 8 to 1°C resulted in a decrease in glycerol uptake with a Q(10) of 3.2 in heart and 2.4 in RBCs. Acclimation to ∼1.5°C did not result in an adaptive enhancement of glycerol uptake as rates were unchanged in heart and RBCs. Glycerol uptake at 1°C was by passive diffusion in heart as evidenced by a linear relationship between glycerol uptake and extracellular glycerol concentration and a lack of inhibition by phloretin. In contrast, in RBCs, glycerol uptake with respect to glycerol concentration showed two linear relationships with a transition point around 50 mM extracellular glycerol. The slope of the second phase was much steeper and eliminated with the inclusion of phloretin. In RBCs from Atlantic salmon (Salmo salar), a related species that does not accumulate glycerol, glycerol uptake showed only a single linear curve and was not inhibited by phloretin. The data imply a strong facilitated component to glycerol uptake in rainbow smelt RBCs at high glycerol concentrations. We propose this is related to cyclic changes in RBC glycerol content involving a loss of glycerol at the gill and a reaccumulation during passage through the liver.

Effects of Naturally Occurring Aquatic Organic Fractions on 241Am Uptake by Scenedesmus obliquus (Chlorophyceae) and Aeromonas hydrophila (Pseudomonadaceae)

PubMed Central

Giesy, John P.; Paine, Donald

1977-01-01

Naturally occurring organics were extracted from water collected from Skinface Pond near Aiken, S.C. Organics were separated into four nominal diameter size fractions (I, >0.0183; II, 0.0183 to 0.0032; III, 0.0032 to 0.0009; IV, <0.0009 μm) by membrane ultrafiltration and introduced into Scenedesmus obliquus and Aeromonas hydrophila cultures to determine their effects on 241Am availability for uptake. Effects on 241Am uptake were determined in actively growing S. obliquus cultures after 96 h of growth and in dense cultures of nongrowing cells after 4 h. Uptake by A. hydrophila was determined after 4 and 24 h in actively growing cultures. All organic fractions stimulated S. obliquus growth, with the most pronounced effects due to larger organic fractions, whereas no apparent growth stimulation of A. hydrophila was observed for any organic fraction. For both long-term and short-term studies, cellular 241Am concentration (picocuries/cell) increased with increasing 241Am concentration for S. obliquus and A. hydrophila. Fraction IV increased 241Am uptake by both S. obliquus and A. hydrophila during 4-h incubations. During 96-h incubations fraction I was flocculated and cosedimented, with S. obliquus and A. hydrophila cells causing an apparent increase in 241Am uptake. Fractions II and III reduced apparent 241Am uptake by S. obliquus as a result of biological dilution caused by increased algal growth due to the organics. Fraction IV caused a reduction in 241Am uptake by S. obliquus not attributable to biological dilution. Organics increased 241Am uptake by A. hydrophila during 4- and 24-h incubations. A. hydrophila also caused flocculation of fraction I during 96-h incubations. PMID:16345193

Stomatal uptake and stomatal deposition of ozone in isoprene and monoterpene emitting plants.

PubMed

Fares, S; Loreto, F; Kleist, E; Wildt, J

2008-01-01

Volatile isoprenoids were reported to protect plants against ozone. To understand whether this could be the result of a direct scavenging of ozone by these molecules, the stomatal and non-stomatal uptake of ozone was estimated in plants emitting isoprene or monoterpenes. Ozone uptake by holm oak (Quercus ilex, a monoterpene emitter) and black poplar (Populus nigra, an isoprene emitter) was studied in whole plant enclosures (continuously stirred tank reactors, CSTR). The ozone uptake by plants was estimated measuring ozone concentration at the inlet and outlet of the reactors, after correcting for the uptake of the enclosure materials. Destruction of ozone at the cuticle or at the plant stems was found to be negligible compared to the ozone uptake through the stomata. For both plant species, a relationship between stomatal conductance and ozone uptake was found. For the poplar, the measured ozone losses were explained by the uptake of ozone through the stomata only, and ozone destruction by gas phase reactions with isoprene was negligible. For the oak, gas phase reactions of ozone with the monoterpenes emitted by the plants contributed significantly to ozone destruction. This was confirmed by two different experiments showing a) that in cases of high stomatal conductance but under low CO(2) concentration, a reduction of monoterpene emission was still associated with reduced O(3) uptake; and b) that ozone losses due to the gas phase reactions only can be measured when using the exhaust from a plant chamber to determine the gas phase reactivity in an empty reaction chamber. Monoterpenes can therefore relevantly scavenge ozone at leaf level contributing to protection against ozone.

Confocal analysis of hepatocellular long-chain fatty acid uptake.

PubMed

Elsing, C; Winn-Börner, U; Stremmel, W

1995-12-01

Transmembrane transport and cytosolic accumulation of fatty acids were investigated using confocal laser scanning microscopy (cLSM). A Zeiss LSM 310 system was used to determine the uptake of the fluorescent fatty acid derivative 12-(N-methyl)-N-[(7-nitrobenz-2-oxa-1,3- diazol-4-yl)amino]octadecanoic acid (12-NBD stearate) (C18) in single rat hepatocytes. Uptake was a saturable process with a Michaelis-Menten constant value of 68 nM. Initial uptake velocity was dependent on extracellular presence of albumin and beta-lactoglobulin. Absence of albumin reduced uptake to 32 +/- 16% (P < 0.01) of control values. In the presence of unlabeled stearate, uptake of 12-NBD stearate was lowered to 49 +/- 12% (P < 0.01). Ion substitution experiments showed no sodium dependency of uptake. Increase in membrane potential led to a pronounced accumulation of the fatty acid derivative within the plasma membrane and in the adjacent cytoplasmic compartment, whereas membrane depolarization had no effect on uptake rates. In separate experiments line scans through representative hepatocytes were analyzed to generate "x-t" plots. 12-NBD stearate showed a fluorescence pattern with prominent staining of the area of the plasma membrane and the adjacent cytoplasm, dependent on the presence of extracellular albumin. For the hepatocellular cytosolic accumulation process of 12-NBD stearate a diffusion constant of 22.2 +/- 6.2 x 10(-9) cm2/s was calculated. In contrast to the long-chain fatty acid derivative 12-NBD stearate, short (C5)- and medium (C11)-chain fatty acids revealed no membrane interaction with hepatocytes. Erythrocytes also lacked a membrane interaction process for 12-NBD stearate. In conclusion, it was demonstrated that cLSM is capable of directly evaluating the cellular fatty acid uptake process at a subcellular level.

Flavonoid Rutin Increases Thyroid Iodide Uptake in Rats

PubMed Central

Lima Gonçalves, Carlos Frederico; de Souza dos Santos, Maria Carolina; Ginabreda, Maria Gloria; Soares Fortunato, Rodrigo; Pires de Carvalho, Denise; Freitas Ferreira, Andrea Claudia

2013-01-01

Thyroid iodide uptake through the sodium-iodide symporter (NIS) is not only an essential step for thyroid hormones biosynthesis, but also fundamental for the diagnosis and treatment of different thyroid diseases. However, part of patients with thyroid cancer is refractory to radioiodine therapy, due to reduced ability to uptake iodide, which greatly reduces the chances of survival. Therefore, compounds able to increase thyroid iodide uptake are of great interest. It has been shown that some flavonoids are able to increase iodide uptake and NIS expression in vitro, however, data in vivo are lacking. Flavonoids are polyhydroxyphenolic compounds, found in vegetables present in human diet, and have been shown not only to modulate NIS, but also thyroperoxidase (TPO), the key enzyme in thyroid hormones biosynthesis, besides having antiproliferative effect in thyroid cancer cell lines. Therefore, we aimed to evaluate the effect of some flavonoids on thyroid iodide uptake in Wistar rats in vivo. Among the flavonoids tested, rutin was the only one able to increase thyroid iodide uptake, so we decided to evaluate the effect of this flavonoid on some aspects of thyroid hormones synthesis and metabolism. Rutin led to a slight reduction of serum T4 and T3 without changes in serum thyrotropin (TSH), and significantly increased hypothalamic, pituitary and brown adipose tissue type 2 deiodinase and decreased liver type 1 deiodinase activities. Moreover, rutin treatment increased thyroid iodide uptake probably due to the increment of NIS expression, which might be secondary to increased response to TSH, since TSH receptor expression was increased. Thus, rutin might be useful as an adjuvant in radioiodine therapy, since this flavonoid increased thyroid iodide uptake without greatly affecting thyroid function. PMID:24023911

Impact of blood glucose, diabetes, insulin, and obesity on standardized uptake values in tumors and healthy organs on 18F-FDG PET/CT.

PubMed

Büsing, Karen A; Schönberg, Stefan O; Brade, Joachim; Wasser, Klaus

2013-02-01

Chronically altered glucose metabolism interferes with (18)F-FDG uptake in malignant tissue and healthy organs and may therefore lower tumor detection in (18)F-FDG PET/CT. The present study assesses the impact of elevated blood glucose levels (BGL), diabetes, insulin treatment, and obesity on (18)F-FDG uptake in tumors and biodistribution in normal organ tissues. (18)F-FDG PET/CT was analyzed in 90 patients with BGL ranging from 50 to 372 mg/dl. Of those, 29 patients were diabetic and 21 patients had received insulin prior to PET/CT; 28 patients were obese with a body mass index >25. The maximum standardized uptake value (SUV(max)) of normal organs and the main tumor site was measured. Differences in SUV(max) in patients with and without elevated BGLs, diabetes, insulin treatment, and obesity were compared and analyzed for statistical significance. Increased BGLs were associated with decreased cerebral FDG uptake and increased uptake in skeletal muscle. Diabetes and insulin diminished this effect, whereas obesity slightly enhanced the outcome. Diabetes and insulin also increased the average SUV(max) in muscle cells and fat, whereas the mean cerebral SUV(max) was reduced. Obesity decreased tracer uptake in several healthy organs by up to 30%. Tumoral uptake was not significantly influenced by BGL, diabetes, insulin, or obesity. Changes in BGLs, diabetes, insulin, and obesity affect the FDG biodistribution in muscular tissue and the brain. Although tumoral uptake is not significantly impaired, these findings may influence the tumor detection rate and are therefore essential for diagnosis and follow-up of malignant diseases. Copyright © 2013 Elsevier Inc. All rights reserved.

Exploring the effect of silver nanoparticle size and medium composition on uptake into pulmonary epithelial 16HBE14o-cells

NASA Astrophysics Data System (ADS)

Kettler, Katja; Krystek, Petra; Giannakou, Christina; Hendriks, A. Jan; de Jong, Wim H.

2016-07-01

The increasing number of nanotechnology products on the market poses increasing human health risks by particle exposures. Adverse effects of silver nanoparticles (AgNPs) in various cell lines have been measured based on exposure dose after a fixed time point, but NP uptake kinetics and the time-dependent internal cellular concentration are often not considered. Even though knowledge about relevant timescales for NP uptake is essential, e.g. for time- and cost-effective risk assessment through modelling, insufficient data are available. Therefore, the authors examined uptake rates for three different AgNP sizes (20, 50 and 75 nm) and two tissue culture medium compositions (with and without foetal calf serum, FCS) under realistic exposure concentrations in pulmonary epithelial 16HBE14o-cells. The quantification of Ag in cells was carried out by high-resolution inductively coupled plasma mass spectrometry. We show for the first time that uptake kinetics of AgNPs into 16HBE14o-cells was highly influenced by medium composition. Uptake into cells was higher in medium without FCS, reaching approximately twice the concentration after 24 h than in medium supplemented with FCS, showing highest uptake for 50-nm AgNPs when expressed on a mass basis. This optimum shifts to 20 nm on a number basis, stressing the importance of the measurand in which results are presented. The importance of our research identifies that not just the uptake after a certain time point should be considered as dose but also the process of uptake (timing) might need to be considered when studying the mechanism of toxicity of nanoparticles.

Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

USGS Publications Warehouse

Hall, R.O.; Tank, J.L.; Sobota, D.J.; Mulholland, P.J.; O'Brien, J. M.; Dodds, W.K.; Webster, J.R.; Valett, H.M.; Poole, G.C.; Peterson, B.J.; Meyer, J.L.; McDowell, W.H.; Johnson, S.L.; Hamilton, S.K.; Grimm, N. B.; Gregory, S.V.; Dahm, Clifford N.; Cooper, L.W.; Ashkenas, L.R.; Thomas, S.M.; Sheibley, R.W.; Potter, J.D.; Niederlehner, B.R.; Johnson, L.T.; Helton, A.M.; Crenshaw, C.M.; Burgin, A.J.; Bernot, M.J.; Beaulieu, J.J.; Arangob, C.P.

2009-01-01

We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO-3 concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO-3 uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S Wtot). Uptake length increased with specific discharge (Q/w) and increasing NO-3 concentrations, showing a loss in removal efficiency in streams with high NO-3 concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO-3 removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO-3 uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO-3 uptake lengths via directly increasing both gross primary production and NO-3 concentration. Gross primary production shortened SWtot, while increasing NO-3 lengthened SWtot resulting in no net effect of land use on NO- 3 removal. ?? 2009.

A role for sodium-chloride cotransporters in the rapid regulation of ion uptake following acute environmental acidosis: new insights from the zebrafish model

PubMed Central

Perry, Steve F.

2016-01-01

The effects of acute exposure to acidic water on Na+ and Cl− homeostasis, and the mechanisms underlying their compensatory regulation, were investigated in the larval zebrafish Danio rerio. Exposure to acidic water (pH 4.0; control pH 7.6) for 2 h significantly reduced Na+ uptake and whole body Na+ content. Nevertheless, the capacity for Na+ uptake was substantially increased in fish preexposed to acidic water but measured in control water. Based on the accumulation of the Na+-selective dye, Sodium Green, two ionocyte subtypes exhibited intracellular Na+ enrichment after preexposure to acidic water: H+-ATPase rich (HR) cells, which coexpress the Na+/H+ exchanger isoform 3b (NHE3b), and a non-HR cell population. In fish experiencing Na+-Cl− cotransporter (NCC) knockdown, we observed no Sodium Green accumulation in the latter cell type, suggesting the non-HR cells were NCC cells. Elimination of NHE3b-expressing HR cells did not prevent the increased Na+ uptake following acid exposure. On the other hand, the increased Na+ uptake was abolished when the acidic water was enriched with Na+ and Cl−, but not with Na+ only, indicating that the elevated Na+ uptake after acid exposure was associated with the compensatory regulation of Cl−. Further examinations demonstrated that acute acid exposure also reduced whole body Cl− levels and increased the capacity for Cl− uptake. Moreover, knockdown of NCC prevented the increased uptake of both Na+ and Cl− after exposure to acidic water. Together, the results of the present study revealed a novel role of NCC in the compensatory regulation of Na+ and Cl− uptake following acute acidosis. PMID:27784676

Reduction in clonogenic survival of sodium-iodide symporter (NIS)-positive cells following intracellular uptake of (99m)Tc versus (188)Re.

PubMed

Freudenberg, Robert; Wendisch, Maria; Runge, Roswitha; Wunderlich, Gerd; Kotzerke, Jörg

2012-12-01

Cellular radionuclide uptake increases the heterogeneity of absorbed dose to biological structures. Dose increase depends on uptake yield and emission characteristics of radioisotopes. We used an in vitro model to compare the impact of cellular uptake of (188)Re-perrhenate and (99m)Tc-pertechnetate on cellular survival. Rat thyroid PC Cl3 cells in culture were incubated with (188)Re or (99m)Tc in the presence or absence of perchlorate for 1 hour. Clonogenic cell survival was measured by colony formation. In addition, intracellular radionuclide uptake was quantified. Dose effect curves were established for (188)Re and (99m)Tc for various extra- and intracellular distributions of the radioactivity. In the presence of perchlorate, no uptake of radionuclides was detected and (188)Re reduced cell survival more efficiently than (99m)Tc. A(37), the activity that is necessary to yield 37% cell survival was 14 MBq/ml for (188)Re and 480 MBq/ml for (99m)Tc. In the absence of perchlorate, both radionuclides showed similar uptakes; however, A(37) was reduced by 30% for the beta-emitter and by 95% for (99m)Tc. The dose D(37) that yields 37% cell survival was between 2.3 and 2.8 Gy for both radionuclides. Uptake of (188)Re and (99m)Tc decreased cell survival. Intracellular (99m)Tc yielded a dose increase that was higher compared to (188)Re due to emitted Auger and internal conversion-electrons. Up to 5 Gy there was no difference in radiotoxicity of (188)Re and (99m)Tc. At doses higher than 5 Gy intracellular (99m)Tc became less radiotoxic than (188)Re, probably due to a non-uniform lognormal radionuclide uptake.

Limited effects of exogenous glucose during severe hypoxia and a lack of hypoxia-stimulated glucose uptake in isolated rainbow trout cardiac muscle

PubMed Central

Becker, Tracy A.; DellaValle, Brian; Gesser, Hans; Rodnick, Kenneth J.

2013-01-01

SUMMARY We examined whether exogenous glucose affects contractile performance of electrically paced ventricle strips from rainbow trout under conditions known to alter cardiomyocyte performance, ion regulation and energy demands. Physiological levels of d-glucose did not influence twitch force development for aerobic preparations (1) paced at 0.5 or 1.1 Hz, (2) at 15 or 23°C, (3) receiving adrenergic stimulation or (4) during reoxygenation with or without adrenaline after severe hypoxia. Contractile responses to ryanodine, an inhibitor of Ca2+ release from the sarcoplasmic reticulum, were also not affected by exogenous glucose. However, glucose did attenuate the fall in twitch force during severe hypoxia. Glucose uptake was assayed in non-contracting ventricle strips using 2-[3H] deoxy-d-glucose (2-DG) under aerobic and hypoxic conditions, at different incubation temperatures and with different inhibitors. Based upon a lack of saturation of 2-DG uptake and incomplete inhibition of uptake by cytochalasin B and d-glucose, 2-DG uptake was mediated by a combination of facilitated transport and simple diffusion. Hypoxia stimulated lactate efflux sixfold to sevenfold with glucose present, but did not increase 2-DG uptake or reduce lactate efflux in the presence of cytochalasin B. Increasing temperature (14 to 24°C) also did not increase 2-DG uptake, but decreasing temperature (14 to 4°C) reduced 2-DG uptake by 45%. In conclusion, exogenous glucose improves mechanical performance under hypoxia but not under any of the aerobic conditions applied. The extracellular concentration of glucose and cold temperature appear to determine and limit cardiomyocyte glucose uptake, respectively, and together may help define a metabolic strategy that relies predominantly on intracellular energy stores. PMID:23685969

Cell Type-Specific Modulation of Cobalamin Uptake by Bovine Serum

PubMed Central

Zhao, Hua; Ruberu, Kalani; Li, Hongyun; Garner, Brett

2016-01-01

Tracking cellular 57Co-labelled cobalamin (57Co-Cbl) uptake is a well-established method for studying Cbl homeostasis. Previous studies established that bovine serum is not generally permissive for cellular Cbl uptake when used as a supplement in cell culture medium, whereas supplementation with human serum promotes cellular Cbl uptake. The underlying reasons for these differences are not fully defined. In the current study we address this question. We extend earlier observations by showing that fetal calf serum inhibits cellular 57Co-Cbl uptake by HT1080 cells (a fibrosarcoma-derived fibroblast cell line). Furthermore, we discovered that a simple heat-treatment protocol (95°C for 10 min) ameliorates this inhibitory activity for HT1080 cell 57Co-Cbl uptake. We provide evidence that the very high level of haptocorrin in bovine serum (as compared to human serum) is responsible for this inhibitory activity. We suggest that bovine haptocorrin competes with cell-derived transcobalamin for Cbl binding, and that cellular Cbl uptake may be minimised in the presence of large amounts of bovine haptocorrin that are present under routine in vitro cell culture conditions. In experiments conducted with AG01518 cells (a neonatal foreskin-derived fibroblast cell line), overall cellular 57Co-Cbl uptake was 86% lower than for HT1080 cells, cellular TC production was below levels detectable by western blotting, and heat treatment of fetal calf serum resulted in only a modest increase in cellular 57Co-Cbl uptake. We recommend a careful assessment of cell culture protocols should be conducted in order to determine the potential benefits that heat-treated bovine serum may provide for in vitro studies of mammalian cell lines. PMID:27893837

Rifaximin suppresses background intestinal 18F-FDG uptake on PET/CT scans.

PubMed

Franquet, Elisa; Palmer, Mathew R; Gifford, Anne E; Selen, Daryl J; Chen, Yih-Chieh S; Sedora-Roman, Neda; Joyce, Robin M; Kolodny, Gerald M; Moss, Alan C

2014-10-01

Identification of cancer or inflammatory bowel disease in the intestinal tract by PET/computed tomography (CT) imaging can be hampered by physiological uptake of F-fluorodeoxyglucose (F-FDG) in the normal colon. Previous work has localized this F-FDG uptake to the intestinal lumen, predominantly occupied by bacteria. We sought to determine whether pretreatment with an antibiotic could reduce F-FDG uptake in the healthy colon. Thirty patients undergoing restaging PET/CT for nongastrointestinal lymphoma were randomly selected to receive rifaximin 550 mg twice daily for 2 days before their scan (post-rifaximin). Their PET/CT images were compared with those from their prior study (pre-rifaximin). Cecal maximum standard uptake value (SUVmax) and overall colonic F-FDG uptake were compared between scans. All PET/CT images were blindly scored by a radiologist. The same comparison of sequential scans was also undertaken in 30 patients who did not receive antibiotics. Thirty post-rifaximin scans were compared with 30 pre-rifaximin scans in the same patients. SUVmax in the cecum was significantly lower in the patient's post-rifaximin scans than in their pre-rifaximin scans (P=0.002). The percentage of scans with greater than grade 1 colonic F-FDG uptake was significantly lower in the post-rifaximin scans than in the pre-rifaximin scans (P<0.05). In contrast, there was no significant difference in the paired sequential scans from control patients, nor a reduction in the percentage of scans with greater than grade 1 colonic F-FDG uptake. This pilot study shows that treatment with rifaximin for 2 days before PET/CT scanning can significantly reduce physiological F-FDG uptake in the normal colonic lumen.

Transport and biotransformation of the new cytostatic complex cis-diammineplatinum(II)-chlorocholylglycinate (Bamet-R2) by the rat liver.

PubMed

Macias, R I; Monte, M J; El-Mir, M Y; Villanueva, G R; Marin, J J

1998-09-01

Rat liver uptake and bile output of the cytostatic complex cis-diammineplatinum(II)-chlorocholylglycinate (Bamet-R2) were studied. Up to 100 microM, Bamet-R2 uptake by rat hepatocytes in primary culture followed saturation kinetics (Vmax = 0.65 +/- 0.12 nmol/5 min per mg protein; K(M) = 45.2 +/- 10.7 microM). Bamet-R2 uptake was lower than that of cholylglycinate (CG) but higher than that of cisplatin. Replacement of 116 mM NaCl by 116 mM choline chloride did not significantly reduce Bamet-R2 uptake. Addition of 500 microM CG, cholic acid, estrone sulfate, or ouabain to 50 microM Bamet-R2-containing incubation media inhibited Bamet-R2 uptake. No liver biotransformation of Bamet-R2 occurred, as indicated by HPLC analysis of bile collected from anesthetized rats after intravenous administration of the drug. Bamet-R2 uptake and secretion into bile by isolated rat livers exceeded those of cisplatin but were lower than those of CG. Differences between Bamet-R2 and CG were more marked for bile output than for liver uptake. Thus, higher Bamet-R2 than CG or cisplatin liver content was found. Co-administration of Bamet-R2 and CG revealed that CG induced a slight reduction in Bamet-R2 uptake and a marked inhibition in Bamet-R2 bile output. By contrast, Bamet-R2 had no effect on CG on either liver uptake or bile output. In sum, the present data indicate that Bamet-R2 is efficiently taken up and secreted into bile by the rat liver by mechanisms shared in part by natural bile acids.

Applying standardized uptake values in gallium-67-citrate single-photon emission computed tomography/computed tomography studies and their correlation with blood test results in representative organs.

PubMed

Toriihara, Akira; Daisaki, Hiromitsu; Yamaguchi, Akihiro; Yoshida, Katsuya; Isogai, Jun; Tateishi, Ukihide

2018-05-21

Recently, semiquantitative analysis using standardized uptake value (SUV) has been introduced in bone single-photon emission computed tomography/computed tomography (SPECT/CT). Our purposes were to apply SUV-based semiquantitative analytic method for gallium-67 (Ga)-citrate SPECT/CT and to evaluate correlation between SUV of physiological uptake and blood test results in representative organs. The accuracy of semiquantitative method was validated using an National Electrical Manufacturers Association body phantom study (radioactivity ratio of sphere : background=4 : 1). Thereafter, 59 patients (34 male and 25 female; mean age, 66.9 years) who had undergone Ga-citrate SPECT/CT were retrospectively enrolled in the study. A mean SUV of physiological uptake was calculated for the following organs: the lungs, right atrium, liver, kidneys, spleen, gluteal muscles, and bone marrow. The correlation between physiological uptakes and blood test results was evaluated using Pearson's correlation coefficient. The phantom study revealed only 1% error between theoretical and actual SUVs in the background, suggesting the sufficient accuracy of scatter and attenuation corrections. However, a partial volume effect could not be overlooked, particularly in small spheres with a diameter of less than 28 mm. The highest mean SUV was observed in the liver (range: 0.44-4.64), followed by bone marrow (range: 0.33-3.60), spleen (range: 0.52-2.12), and kidneys (range: 0.42-1.45). There was no significant correlation between hepatic uptake and liver function, renal uptake and renal function, or bone marrow uptake and blood cell count (P>0.05). The physiological uptake in Ga-citrate SPECT/CT can be represented as SUVs, which are not significantly correlated with corresponding blood test results.

Pharmacological and gene regulation properties point to the SlHAK5 K+ transporter as a system for high-affinity Cs+ uptake in tomato plants.

PubMed

Ródenas, Reyes; Nieves-Cordones, Manuel; Rivero, Rosa M; Martinez, Vicente; Rubio, Francisco

2018-04-01

Potassium (K + ) and cesium (Cs + ) are chemically similar but while K + is an essential nutrient, Cs + can be toxic for living organisms, plants included. Two different situations could lead to problems derived from the presence of Cs + in agricultural systems: (1) presence of Cs + at high concentrations that could produce toxic effects on plants, (2) presence of micromolar concentrations of radiocesium, which can be accumulated in the plant and affect animal and human health through the food chain. While K + uptake has been well described in tomato plants, information on molecular mechanisms involved in Cs + accumulation in this species is absent. Here, we show that in tomato plants, high concentrations of Cs + produce deficiency of K + but do not induce high-affinity K + uptake or the gene encoding the high-affinity K + transporter SlHAK5. At these concentrations, Cs + uptake takes place through a Ca 2+ -sensitive pathway, probably a non-selective cation channel. At micromolar concentrations, Cs + is accumulated by a high-affinity uptake system upregulated in K + -starved plants. This high-affinity Cs + uptake shares features with high-affinity K + uptake. It is sensitive to NH 4 + and insensitive to Ba 2+ and Ca 2+ and its presence parallels the pattern of SlHAK5 expression. Moreover, blockers of reactive oxygen species and ethylene action repress SlHAK5 and negatively regulate both high-affinity K + and Cs + uptake. Thus, we propose that SlHAK5 contributes to Cs + uptake from micromolar concentrations in tomato plants and can constitute a pathway for radiocesium transfer from contaminated areas to the food chain. © 2017 Scandinavian Plant Physiology Society.

Use of Mechanistic Modeling to Assess Interindividual Variability and Interspecies Differences in Active Uptake in Human and Rat Hepatocytes

PubMed Central

Ménochet, Karelle; Kenworthy, Kathryn E.; Houston, J. Brian

2012-01-01

Interindividual variability in activity of uptake transporters is evident in vivo, yet limited data exist in vitro, confounding in vitro-in vivo extrapolation. The uptake kinetics of seven organic anion-transporting polypeptide substrates was investigated over a concentration range in plated cryopreserved human hepatocytes. Active uptake clearance (CLactive, u), bidirectional passive diffusion (Pdiff), intracellular binding, and metabolism were estimated for bosentan, pitavastatin, pravastatin, repaglinide, rosuvastatin, telmisartan, and valsartan in HU4122 donor using a mechanistic two-compartment model in Matlab. Full uptake kinetics of rosuvastatin and repaglinide were also characterized in two additional donors, whereas for the remaining drugs CLactive, u was estimated at a single concentration. The unbound affinity constant (Km, u) and Pdiff values were consistent across donors, whereas Vmax was on average up to 2.8-fold greater in donor HU4122. Consistency in Km, u values allowed extrapolation of single concentration uptake activity data and assessment of interindividual variability in CLactive across donors. The maximal contribution of active transport to total uptake differed among donors, for example, 85 to 96% and 68 to 87% for rosuvastatin and repaglinide, respectively; however, in all cases the active process was the major contributor. In vitro-in vivo extrapolation indicated a general underprediction of hepatic intrinsic clearance, an average empirical scaling factor of 17.1 was estimated on the basis of seven drugs investigated in three hepatocyte donors, and donor-specific differences in empirical factors are discussed. Uptake Km, u and CLactive, u were on average 4.3- and 7.1-fold lower in human hepatocytes compared with our previously published rat data. A strategy for the use of rat uptake data to facilitate the experimental design in human hepatocytes is discussed. PMID:22665271

Mechanisms of Hg(II) uptake and methylation in methylating bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morel, Francois M. M.

2016-10-14

The goal of this project was to understand the critical factors which control the availability and transport of Hg(II) into cells, a first step in the production of the neurotoxin, methylmercury. Specifically, this research focused on understanding the mechanism of bacterial mercury uptake and how mercury speciation affects the specificity and kinetics of mercury transport. Our research has shown that Hg(II) uptake in three different iron and sulfate-reducing proteobacteria occurs by the following mechanism (1) : Hg(II) uptake is an active transport process requiring energy, (2) it is dependent upon the structure of the Hg binding ligand, and (3) itmore » is mediated by a heavy metal transporter such as one which transports the essential metal, Zn(II). In order to determine whether this mechanism extends to more diverse phylogenetic groups, we have begun examining Hg(II) uptake and bioavailability in two representative Hg methylating strains within the Firmicutes. These organisms have remarkably different membrane structures distinct from the Proteobacteria. Our results show low uptake rates in these two species of Firmicutes relative to the previously characterized Proteobacteria. This may explain the low methylation rates and yields observed in these organisms. Most surprisingly, however, these organisms appear to take up Hg(II) passively, as the addition of a protonophore failed to reduce Hg(II) uptake in these organisms. This is quite different to what has been observed previously for the Proteobacteria and suggests a different mechanism for Hg(II) uptake in the Firmicutes. We are continuing to understand and describe Hg(II) uptake in these organisms. A manuscript is expected to be submitted on this research in June 2016.« less

Time-course of effects of external beam radiation on [18F]FDG uptake in healthy tissue and bone marrow.

PubMed

Kesner, Adam L; Lau, Victoria K; Speiser, Michael; Hsueh, Wei-Ann; Agazaryan, Nzhde; DeMarco, John J; Czernin, Johannes; Silverman, Daniel H S

2008-06-23

The utility of PET for monitoring responses to radiation therapy have been complicated by metabolically active processes in surrounding normal tissues. We examined the time-course of [18F]FDG uptake in normal tissues using small animal-dedicated PET during the 2 month period following external beam radiation. Four mice received 12 Gy of external beam radiation, in a single fraction to the left half of the body. Small animal [18F]FDG-PET scans were acquired for each mouse at 0 (pre-radiation), 1, 2, 3, 4, 5, 8, 12, 19, 24, and 38 days following irradiation. [18F]FDG activity in various tissues was compared between irradiated and non-irradiated body halves before, and at each time point after irradiation. Radiation had a significant impact on [18F]FDG uptake in previously healthy tissues, and time-course of effects differed in different types of tissues. For example, liver tissue demonstrated increased uptake, particularly over days 3-12, with the mean left to right uptake ratio increasing 52% over mean baseline values (p < 0.0001). In contrast, femoral bone marrow uptake demonstrated decreased uptake, particularly over days 2-8, with the mean left to right uptake ratio decreasing 26% below mean baseline values (p = 0.0005). Significant effects were also seen in lung and brain tissue. Radiation had diverse effects on [18F]FDG uptake in previously healthy tissues. These kinds of data may help lay groundwork for a systematically acquired database of the time-course of effects of radiation on healthy tissues, useful for animal models of cancer therapy imminently, as well as interspecies extrapolations pertinent to clinical application eventually.

Time‐course of effects of external beam radiation on [18F]FDG uptake in healthy tissue and bone marrow

PubMed Central

Kesner, Adam L; Lau, Victoria K; Speiser, Michael; Hsueh, Wei‐Ann; Agazaryan, Nzhde; DeMarco, John J; Czernin, Johannes

2008-01-01

The utility of PET for monitoring responses to radiation therapy have been complicated by metabolically active processes in surrounding normal tissues. We examined the time‐course of [18F]FDG uptake in normal tissues using small animal‐dedicated PET during the 2 month period following external beam radiation. Four mice received 12 Gy of external beam radiation, in a single fraction to the left half of the body. Small animal [18F]FDG‐PET scans were acquired for each mouse at 0 (pre‐radiation), 1, 2, 3, 4, 5, 8, 12, 19, 24, and 38 days following irradiation. [18F]FDG activity in various tissues was compared between irradiated and non‐irradiated body halves before, and at each time point after irradiation. Radiation had a significant impact on [18F]FDG uptake in previously healthy tissues, and time‐course of effects differed in different types of tissues. For example, liver tissue demonstrated increased uptake, particularly over days 3–12, with the mean left to right uptake ratio increasing 52% over mean baseline values (p<0.0001). In contrast, femoral bone marrow uptake demonstrated decreased uptake, particularly over days 2–8, with the mean left to right uptake ratio decreasing 26% below mean baseline values (p=0.0005). Significant effects were also seen in lung and brain tissue. Radiation had diverse effects on [18F]FDG uptake in previously healthy tissues. These kinds of data may help lay groundwork for a systematically acquired database of the time‐course of effects of radiation on healthy tissues, useful for animal models of cancer therapy imminently, as well as interspecies extrapolations pertinent to clinical application eventually. PACs Number: 87.50.‐a

Temperature responses of carbon monoxide and hydrogen uptake by vegetated and unvegetated volcanic cinders

PubMed Central

King, Caitlin E; King, Gary M

2012-01-01

Ecosystem succession on a large deposit of volcanic cinders emplaced on Kilauea Volcano in 1959 has resulted in a mosaic of closed-canopy forested patches and contiguous unvegetated patches. Unvegetated and unshaded surface cinders (Bare) experience substantial diurnal temperature oscillations ranging from moderate (16 °C) to extreme (55 °C) conditions. The surface material of adjacent vegetated patches (Canopy) experiences much smaller fluctuations (14–25 °C) due to shading. To determine whether surface material from these sites showed adaptations by carbon monoxide (CO) and hydrogen (H2) consumption to changes in ambient temperature regimes accompanying succession, we measured responses of CO and H2 uptake to short-term variations in temperature and long-term incubations at elevated temperature. Based on its broader temperature optimum and lower activation energy, Canopy H2 uptake was less sensitive than Bare H2 uptake to temperature changes. In contrast, Bare and Canopy CO uptake responded similarly to temperature during short-term incubations, indicating no differences in temperature sensitivity. However, during extended incubations at 55 °C, CO uptake increased for Canopy but not Bare material, which indicated that the former was capable of thermal adaptation. H2 uptake for material from both sites was completely inhibited at 55 °C throughout extended incubations. These results indicated that plant development during succession did not elicit differences in short-term temperature responses for Bare and Canopy CO uptake, in spite of previously reported differences in CO oxidizer community composition, and differences in average daily and extreme temperatures. Differences associated with vegetation due to succession did, however, lead to a notable capacity for thermophilic CO uptake by Canopy but not Bare material. PMID:22258097

Exploring the effect of silver nanoparticle size and medium composition on uptake into pulmonary epithelial 16HBE14o-cells.

PubMed

Kettler, Katja; Krystek, Petra; Giannakou, Christina; Hendriks, A Jan; de Jong, Wim H

The increasing number of nanotechnology products on the market poses increasing human health risks by particle exposures. Adverse effects of silver nanoparticles (AgNPs) in various cell lines have been measured based on exposure dose after a fixed time point, but NP uptake kinetics and the time-dependent internal cellular concentration are often not considered. Even though knowledge about relevant timescales for NP uptake is essential, e.g. for time- and cost-effective risk assessment through modelling, insufficient data are available. Therefore, the authors examined uptake rates for three different AgNP sizes (20, 50 and 75 nm) and two tissue culture medium compositions (with and without foetal calf serum, FCS) under realistic exposure concentrations in pulmonary epithelial 16HBE14o-cells. The quantification of Ag in cells was carried out by high-resolution inductively coupled plasma mass spectrometry. We show for the first time that uptake kinetics of AgNPs into 16HBE14o-cells was highly influenced by medium composition. Uptake into cells was higher in medium without FCS, reaching approximately twice the concentration after 24 h than in medium supplemented with FCS, showing highest uptake for 50-nm AgNPs when expressed on a mass basis. This optimum shifts to 20 nm on a number basis, stressing the importance of the measurand in which results are presented. The importance of our research identifies that not just the uptake after a certain time point should be considered as dose but also the process of uptake (timing) might need to be considered when studying the mechanism of toxicity of nanoparticles.

Interventions targeted at women to encourage the uptake of cervical screening

PubMed Central

Everett, Thomas; Bryant, Andrew; Griffin, Michelle F; Martin-Hirsch, Pierre PL; Forbes, Carol A; Jepson, Ruth G

2014-01-01

Background World-wide, cervical cancer is the second most common cancer in women. Increasing the uptake of screening, alongside increasing informed choice is of great importance in controlling this disease through prevention and early detection. Objectives To assess the effectiveness of interventions aimed at women, to increase the uptake, including informed uptake, of cervical cancer screening. Search methods We searched the Cochrane Gynaecological Cancer Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Issue 1, 2009. MEDLINE, EMBASE and LILACS databases up to March 2009. We also searched registers of clinical trials, abstracts of scientific meetings, reference lists of included studies and contacted experts in the field. Selection criteria Randomised controlled trials (RCTs) of interventions to increase uptake/informed uptake of cervical cancer screening. Data collection and analysis Two review authors independently abstracted data and assessed risk of bias. Where possible the data were synthesised in a meta-analysis. Main results Thirty-eight trials met our inclusion criteria. These trials assessed the effectiveness of invitational and educational interventions, counselling, risk factor assessment and procedural interventions. Heterogeneity between trials limited statistical pooling of data. Overall, however, invitations appear to be effective methods of increasing uptake. In addition, there is limited evidence to support the use of educational materials. Secondary outcomes including cost data were incompletely documented so evidence was limited. Most trials were at moderate risk of bias. Informed uptake of cervical screening was not reported in any trials. Authors’ conclusions There is evidence to support the use of invitation letters to increase the uptake of cervical screening. There is limited evidence to support educational interventions but it is unclear what format is most effective. The majority of the studies are from developed countries and so the relevance to developing countries is unclear. PMID:21563135

Nutrient uptake and growth responses of Virginia pine to elevated atmospheric carbon dioxide. [Pisolithus tinctorius, Pinus virginiana Mill

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luxmoore, R.J.; O'Neill, E.G.; Ells, J.M.

One-year-old Virgina pine (Pinus virginiana Mill.) seedlings with native or Pisolithus tinctorius mycorrhizal associations were grown in pots with soil low in organic matter and in cation exchange capacity and were exposed to one of five atmospheric CO/sub 2/ levels in the range of 340 to 940 ..mu..L/L in open-top field chambers. The mean dry weight of the seedlings increased from 4.4 to 11.0 g/plant during the 122-d exposure period. Significant increases in dry weight and uptake of N, Ca, Al, Fe, Zn, and Sr occurred with CO/sub 2/ enrichment. Greater chemical uptake was associated with greater root weight. Specificmore » absorption rates for chemicals (uptake per gram of root per day) were generally not affected by CO/sub 2/ enrichment. The uptake of P and K was not increased with elevated CO/sub 2/, and these elements showed the greater nutrient-use efficiency (C gain per element uptake). The nutrient-use efficiency for N and Ca was not influenced by atmospheric CO/sub 2/ enrichment. Large increases in Zn uptake at high CO'' suggested an increase in rhizosphere acidification, which may have resulted from the release of protons from the roots, since it was estimated that cation uptake increasingly exceeded anion uptake with CO/sub 2/ enrichment. Potassium, P, and NO/sub 3//sup -/ concentrations in the pot leachate decreased with higher CO/sub 2/ levels, and a similar trend was found for Al and Mg. These results suggest that soil-plant systems may exhibit increased nutrient and chemical retention at elevated atmospheric CO/sub 2/.« less

Muscarinic receptor stimulation of D-aspartate uptake into human SH-SY5Y neuroblastoma cells is attenuated by hypoosmolarity.

PubMed

Foster, Daniel J; Heacock, Anne M; Fisher, Stephen K

2010-04-01

In addition to its function as an excitatory neurotransmitter, glutamate plays a major role as an osmolyte within the central nervous system (CNS). Accordingly, mechanisms that regulate glutamate release and uptake are of physiological importance not only during conditions in which cell volume remains constant but also when cells are subjected to hypoosmotic stress. In the present study, the ability of muscarinic cholinergic receptors (mAChRs) to regulate the uptake of glutamate (monitored as D-aspartate) into human SH-SY5Y neuroblastoma cells under isotonic or hypotonic conditions has been examined. In isotonic media, agonist activation of mAChRs resulted in a significant increase (250-300% of control) in the uptake of D-aspartate and, concurrently, a cellular redistribution of the excitatory amino acid transporter 3 (EAAT3) to the plasma membrane. mAChR-mediated increases in d-aspartate uptake were potently blocked by the EAAT3 inhibitor l-beta-threo-benzyl-aspartate. In hypotonic media, the ability of mAChR activation to facilitate D-aspartate uptake was significantly attenuated (40-50%), and the cellular distribution of EAAT3 was disrupted. Reduction of mAChR-stimulated D-aspartate uptake under hypoosmotic conditions could be fully reversed upon re-exposure of the cells to isotonic media. Under both isotonic and hypotonic conditions, mAChR-mediated increases in D-aspartate uptake depended on cytoskeletal integrity, protein kinase C and phosphatidylinositol 3-kinase activities, and the availability of intracellular Ca2+. In contrast, dependence on extracellular Ca2+ was observed only under isotonic conditions. The results suggest that, although the uptake of D-aspartate into SH-SY5Y cells is enhanced after mAChR activation, this process is markedly attenuated by hypoosmolarity.

Cutoff value of thyroid uptake of (99m)Tc-pertechnetate to discriminate between Graves' disease and painless thyroiditis: a single center retrospective study.

PubMed

Uchida, Toyoyoshi; Suzuki, Ruriko; Kasai, Takatoshi; Onose, Hiroyuki; Komiya, Koji; Goto, Hiromasa; Takeno, Kageumi; Ishii, Shinya; Sato, Junko; Honda, Akira; Kawano, Yui; Himuro, Miwa; Yamada, Emiko; Yamada, Tetsu; Watada, Hirotaka

2016-01-01

Thyroid uptake of (99m)Tc-pertechnetate is a useful way to determine the cause of thyrotoxicosis. In daily clinical practice, (99m)Tc-pertechnetate uptake is used to discriminate between Graves' disease and painless thyroiditis when clinical information is not enough to make the distinction. However, since the optimal cutoff value of (99m)Tc-pertechnetate uptake has not yet been elucidated, our aim was to determine this value. We recruited patients with thyrotoxicosis in whom (99m)Tc-pertechnetate uptake was measured in clinical settings between 2009 and 2013. Three experienced endocrinologists (who were blinded to the value of (99m)Tc-pertechnetate uptake and initial treatment) diagnosed the cause of thyrotoxicosis based on thyrotropin, free triiodothyronine, free thyroxine, and thyrotropin receptor antibody levels, and by ultrasound findings and using images of thyroid uptake of (99m)Tc-pertechnetate without the actual values. Ninety-four patients diagnosed as having Graves' disease or painless thyroiditis were finally included. According to the diagnosis, the optimal cutoff value of (99m)Tc-pertechnetate uptake was determined by receiver operating characteristics analysis. A cutoff value of 1.0% provided optimal sensitivity and specificity of 96.6% and 97.1%, respectively. Then, its validity was confirmed in 78 patients with confirmed Graves' disease or painless thyroiditis diagnosed at another institute. Applying this cutoff value to the patients with thyrotoxicosis revealed positive and negative predictive values for Graves' disease of 100% and 88.9%, respectively. In conclusion, a cutoff value for (99m)Tc-pertechnetate uptake of 1.0% was useful to discriminate between Graves' disease and painless thyroiditis.

Effects of nitrogen and phosphorus additions on soil methane uptake in disturbed forests

NASA Astrophysics Data System (ADS)

Zheng, Mianhai; Zhang, Tao; Liu, Lei; Zhang, Wei; Lu, Xiankai; Mo, Jiangming

2016-12-01

Atmospheric nitrogen (N) deposition is generally thought to suppress soil methane (CH4) uptake in natural forests, and phosphorus (P) input may alleviate this negative effect. However, it remains unclear how N and P inputs control soil CH4 uptake in disturbed forests. In this study, soil CH4 uptake rates were measured in two disturbed forests, including a secondary forest (with previous, but not recent, disturbance) and a plantation forest (with recent continuous disturbance), in southern China for 34 months of N and/or P additions: control, N addition (150 kg N ha-1 yr-1), P addition (150 kg P ha-1 yr-1), and NP addition (150 kg N ha-1 yr-1 plus 150 kg P ha-1 yr-1). Mean CH4 uptake rate in control plots was significantly higher in the secondary forest (24.40 ± 0.81 µg CH4-C m-2 h-1) than in the plantation forest (17.07 ± 0.70 µg CH4-C m-2 h-1). CH4 uptake rate had negative relationships with soil water-filled pore space in both forests. In the secondary forest, N, P, and NP additions significantly decreased CH4 uptake by 39.7%, 27.8%, and 37.6%, respectively, but had no significant effects in the plantation forest, indicating that P input does not alleviate the suppression of CH4 uptake by N deposition. Taken together, our findings suggest that reducing anthropogenic disturbance, including harvesting of forest floor, and anthropogenic N and P inputs will increase soil CH4 uptake in disturbed forests, which is important in view of the increased trends in global warming during recent decades.

Proton-coupled organic cation antiporter-mediated uptake of apomorphine enantiomers in human brain capillary endothelial cell line hCMEC/D3.

PubMed

Okura, Takashi; Higuchi, Kei; Kitamura, Atsushi; Deguchi, Yoshiharu

2014-01-01

R(-)-Apomorphine is a dopamine agonist used for rescue management of motor function impairment associated with levodopa therapy in Parkinson's disease patients. The aim of this study was to examine the role of proton-coupled organic cation antiporter in uptake of R(-)-apomorphine and its S-enantiomer in human brain, using human endothelial cell line hCMEC/D3 as a model. Uptake of R(-)- or S(+)-apomorphine into hCMEC/D3 cells was measured under various conditions to evaluate its time-, concentration-, energy- and ion-dependency. Inhibition by selected organic cations was also examined. Uptakes of both R(-)- and S(+)-apomorphine increased with time. The initial uptake velocities of R(-)- and S(+)-apomorphine were concentration-dependent, with similar Km and Vmax values. The cell-to-medium (C/M) ratio of R(-)-apomorphine was significantly reduced by pretreatment with sodium azide, but was not affected by replacement of extracellular sodium ion with N-methylglucamine or potassium. Intracellular alkalization markedly reduced the uptake, while intracellular acidification increased it, suggesting that the uptake is driven by an oppositely directed proton gradient. The C/M ratio was significantly decreased by amantadine, verapamil, pyrilamine and diphenhydramine (substrates or inhibitors of proton-coupled organic cation antiporter), while tetraethylammonium (substrate of organic cation transporters (OCTs)) and carnitine (substrate of carnitine/organic cation transporter 2; (OCTN2)) had no effect. R(-)-Apomorphine uptake was competitively inhibited by diphenhydramine. Our results indicate that R(-)-apomorphine transport in human blood-brain barrier (BBB) model cells is similar to S(+)-apomorphine uptake. The transport was dependent on an oppositely directed proton gradient, but was sodium- or membrane potential-independent. The transport characteristics were consistent with involvement of the previously reported proton-coupled organic cation antiporter.

Peak oxygen uptake in a sprint interval testing protocol vs. maximal oxygen uptake in an incremental testing protocol and their relationship with cross-country mountain biking performance.

PubMed

Hebisz, Rafał; Hebisz, Paulina; Zatoń, Marek; Michalik, Kamil

2017-04-01

In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak oxygen uptake (V̇O 2peak ) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to maximal oxygen uptake (V̇O 2max ) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased oxygen uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, oxygen uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak oxygen uptake in a sprint interval testing protocol than maximal oxygen uptake attained in an incremental testing protocol demonstrate superior competitive performance.

Temperature responses of carbon monoxide and hydrogen uptake by vegetated and unvegetated volcanic cinders.

PubMed

King, Caitlin E; King, Gary M

2012-08-01

Ecosystem succession on a large deposit of volcanic cinders emplaced on Kilauea Volcano in 1959 has resulted in a mosaic of closed-canopy forested patches and contiguous unvegetated patches. Unvegetated and unshaded surface cinders (Bare) experience substantial diurnal temperature oscillations ranging from moderate (16 °C) to extreme (55 °C) conditions. The surface material of adjacent vegetated patches (Canopy) experiences much smaller fluctuations (14-25 °C) due to shading. To determine whether surface material from these sites showed adaptations by carbon monoxide (CO) and hydrogen (H(2)) consumption to changes in ambient temperature regimes accompanying succession, we measured responses of CO and H(2) uptake to short-term variations in temperature and long-term incubations at elevated temperature. Based on its broader temperature optimum and lower activation energy, Canopy H(2) uptake was less sensitive than Bare H(2) uptake to temperature changes. In contrast, Bare and Canopy CO uptake responded similarly to temperature during short-term incubations, indicating no differences in temperature sensitivity. However, during extended incubations at 55 °C, CO uptake increased for Canopy but not Bare material, which indicated that the former was capable of thermal adaptation. H(2) uptake for material from both sites was completely inhibited at 55 °C throughout extended incubations. These results indicated that plant development during succession did not elicit differences in short-term temperature responses for Bare and Canopy CO uptake, in spite of previously reported differences in CO oxidizer community composition, and differences in average daily and extreme temperatures. Differences associated with vegetation due to succession did, however, lead to a notable capacity for thermophilic CO uptake by Canopy but not Bare material.

Enhancement of Cell Membrane Invaginations, Vesiculation and Uptake of Macromolecules by Protonation of the Cell Surface

PubMed Central

Ben-Dov, Nadav; Korenstein, Rafi

2012-01-01

The different pathways of endocytosis share an initial step involving local inward curvature of the cell’s lipid bilayer. It has been shown that to generate membrane curvature, proteins or lipids enforce transversal asymmetry of the plasma membrane. Thus it emerges as a general phenomenon that transversal membrane asymmetry is the common required element for the formation of membrane curvature. The present study demonstrates that elevating proton concentration at the cell surface stimulates the formation of membrane invaginations and vesiculation accompanied by efficient uptake of macromolecules (Dextran-FITC, 70 kD), relative to the constitutive one. The insensitivity of proton induced uptake to inhibiting treatments and agents of the known endocytic pathways suggests the entry of macromolecules to proceeds via a yet undefined route. This is in line with the fact that neither ATP depletion, nor the lowering of temperature, abolishes the uptake process. In addition, fusion mechanism such as associated with low pH uptake of toxins and viral proteins can be disregarded by employing the polysaccharide dextran as the uptake molecule. The proton induced uptake increases linearly in the extracellular pH range of 6.5 to 4.5, and possesses a steep increase at the range of 4> pH>3, reaching a plateau at pH≤3. The kinetics of the uptake implies that the induced vesicles release their content to the cytosol and undergo rapid recycling to the plasma membrane. We suggest that protonation of the cell’s surface induces local charge asymmetries across the cell membrane bilayer, inducing inward curvature of the cell membrane and consequent vesiculation and uptake. PMID:22558127

Long-chain fatty acid uptake by skeletal muscle is impaired in homozygous, but not heterozygous, heart-type-FABP null mice.

PubMed

Luiken, J J F P; Koonen, D P Y; Coumans, W A; Pelsers, M M A L; Binas, B; Bonen, A; Glatz, J F C

2003-04-01

Previous studies with cardiac myocytes from homozygous heart-type fatty acid (FA)-binding protein (H-FABP) -/- mice have indicated that this intracellular receptor protein for long-chain FA is involved in the cellular uptake of these substrates. Based on the knowledge that muscle FA uptake is a process highly sensitive to regulation by hormonal and mechanical stimuli, we studied whether H-FABP would play a role in this regulation. A suitable model system to answer this question is provided by H-FABP +/- mice, because in hindlimb muscles the content of H-FABP was measured to be 34% compared to wild-type mice. In these H-FABP +/- skeletal muscles, just as in H-FABP -/- muscles, contents of FA transporters, i.e., 43-kDa FABPpm and 88-kDa FAT/CD36, were similar compared to wild-type muscles, excluding possible compensatory mechanisms at the sarcolemmal level. Palmitate uptake rates were measured in giant vesicles prepared from hindlimb muscles of H-FABP -/-, H-FABP +/-, and H-FABP +/+ mice. For comparison, giant vesicles were isolated from liver, the tissue of which expresses a distinct type of FABP (i.e., L-FABP). Whereas in H-FABP -/- skeletal muscle FA uptake was reduced by 42-45%, FA uptake by H-FABP +/- skeletal muscle was not different from that in wild-type mice. In contrast, in liver from H-FABP -/- and from H-FABP +/- mice, FA uptake was not altered compared to wild-type animals, indicating that changes in FA uptake are restricted to H-FABP expressing tissues. It is concluded that H-FABP plays an important, yet merely permissive, role in FA uptake into muscle tissues.

[Myocardial uptake ratio of iodine-123 labeled beta-methyl iodophenylpentadecanoic acid (123I-BMIPP) in relation to the concentration of the substrates of energy].

PubMed

Tsuchimochi, S; Tamaki, N; Kawamoto, M; Tadamura, E; Fujita, T; Nohara, R; Matsumori, A; Sasayama, S; Yonekura, Y; Konishi, J

1995-06-01

Iodine-123 beta-methyl iodophenylpentadecanoic acid (BMIPP) has been used for evaluating myocardial fatty acid metabolism in vivo. The whole body BMIPP imaging was acquired in 26 patients (11 with HCM, 11 with CAD and 4 with DCM) to calculate % uptake in the myocardium and to correlate its uptake with biochemical data, including blood sugar (BS), nonesterified fatty acid (NEFA) and insulin in the blood. BMIPP was administered at rest with overnight fasting state, and the anterior and posterior whole body imaging was performed one hour later. The background corrected whole myocardial counts were calculated to obtain %BMIPP uptake. In addition, the heart to mediastinum count ratio (H/M ratio) was calculated from the mean counts in the heart and the upper mediastinum in the anterior view. The %BMIPP uptake was 3.70 +/- 1.22% and H/M ratio was 2.30 +/- 0.23. The patients with DCM showed higher %BMIPP uptake values (DCM = 5.58 +/- 0.67% vs. CAD = 3.09 +/- 0.97% and HCM = 3.63 +/- 0.86%, both p < 0.01), but similar values of H/M ratio with other patients (DCM = 2.43 +/- 0.20, CAD = 2.22 +/- 0.25 and HCM = 2.32 +/- 0.20). Although the biochemical data varied at the time of the tracer administration, they were not significantly correlated with the %BMIPP uptake or H/M ratio. However, there was a significant correlation between %BMIPP uptake and H/M ratio with the correlation coefficient of 0.80 (p < 0.001). We conclude that the myocardial uptake of BMIPP is not influenced by the plasma substrate level under the fasting state.

Uptake of lactosylated low-density lipoprotein by galactose-specific receptors in rat liver.

PubMed

Bijsterbosch, M K; Van Berkel, T J

1990-08-15

The liver contains two types of galactose receptors, specific for Kupffer and parenchymal cells respectively. These receptors are only expressed in the liver, and therefore are attractive targets for the specific delivery of drugs. We provided low-density lipoprotein (LDL), a particle with a diameter of 23 nm in which a variety of drugs can be incorporated, with terminal galactose residues by lactosylation. Radioiodinated LDL, lactosylated to various extents (60-400 mol of lactose/ mol of LDL), was injected into rats. The plasma clearance and hepatic uptake of radioactivity were correlated with the extent of lactosylation. Highly lactosylated LDL (greater than 300 lactose/LDL) is completely cleared from the blood by liver within 10 min. Pre-injection with N-acetylgalactosamine blocks liver uptake, which indicates that the hepatic recognition sites are galactose-specific. The hepatic uptake occurs mainly by parenchymal and Kupffer cells. At a low degree of lactosylation, approx. 60 lactose/LDL, the specific uptake (ng/mg of cell protein) is 28 times higher in Kupffer cells than in parenchymal cells. However, because of their much larger mass, parenchymal cells are the main site of uptake. At high degrees of lactosylation (greater than 300 lactose/LDL), the specific uptake in Kupffer cells is 70-95 times that in parenchymal cells. Under these conditions, Kupffer cells are, despite their much smaller mass, the main site of uptake. Thus not only the size but also the surface density of galactose on lactosylated LDL is important for the balance of uptake between Kupffer and parenchymal cells. This knowledge should allow us to design particulate galactose-bearing carriers for the rapid transport of various drugs to either parenchymal cells or Kupffer cells.

[Carbon monoxide tests in a steady state. Uptake and transfer capacity, normal values and lower limits].

PubMed

Ramonatxo, M; Préfaut, C; Guerrero, H; Moutou, H; Bansard, X; Chardon, G

1982-01-01

The aim of this study was to establish data which would best demonstrate the variations of different tests using Carbon Monoxide as a tracer gas (total and partial functional uptake coefficient and transfer capacity) to establish mean values and lower limits of normal of these tests. Multivariate statistical analysis was used; in the first stage a connection was sought between the fractional uptake coefficient (partial and total) to other parameters, comparing subjects and data. In the second stage the comparison was refined by eliminating the least useful data, trying, despite a small loss of material, to reveal the most important connections, linear or otherwise. The fractional uptake coefficients varied according to sex, also the variation of the partial alveolar-expired fractional uptake equivalent (DuACO) was largely a function of respiratory rate and tidal volume. The alveolar-arterial partial fractional uptake equivalent (DuaCO) depended more on respiratory frequency and age. Finally the total fractional uptake coefficient (DuCO) and the transfer capacity corrected per liter of ventilation (TLCO/V) were functions of these parameters. The last stage of this work, after taking account of the statistical observations consistent with the facts of these physiological hypotheses led to a search for a better way of approaching the laws linking the collected data to the fractional uptake coefficient. The lower limits of normal were arbitrarily defined, separating those 5% of subjects deviating most strongly from the mean. As a result, the relationship between the lower limit of normal and the theoretical mean value was 90% for the partial and total fractional uptake coefficient and 70% for the transfer capacity corrected per liter of ventilation.

Aquaporins and root water uptake

USDA-ARS?s Scientific Manuscript database

Water is one of the most critical resources limiting plant growth and crop productivity, and root water uptake is an important aspect of plant physiology governing plant water use and stress tolerance. Pathways of root water uptake are complex and are affected by root structure and physiological res...

Ga-67 cardiac uptake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, D.S.; Tipton, R.E.

1983-12-01

A case of positive Ga-67 image due to tuberculous pericarditis is presented. The pattern and distribution of the uptake suggested that the concentration of the activity was mainly in the inflamed pericardium. The known causes of Ga-67 cardiac uptake were reviewed, and a differential diagnosis is given.

Bicyclists' Uptake of Traffic-Related Air Pollution: Effects of the Urban Transportation System

DOT National Transportation Integrated Search

2014-10-27

While bicyclists and other active travelers obtain health benefits from increased physical activity, they also risk uptake of traffic-related air pollution. But pollution uptake by urban bicyclists is not well understood due to a lack of direct measu...

Mammary gland uptake of sodium Tc-pertechnetate in a cat with a drug-induced gynecomastia.

PubMed

Patricelli, A J; Lappin, M R; Steyn, P F

1999-01-01

Sodium Tc-pertechnetate accumulated in the mammary glands of a male cat. It was determined that the uptake was attributable to gynecomastia induced by medroxyprogesterone acetate injections. Gynecomastia and pertechnetate uptake resolved following cessation of medroxyprogesterone acetate treatment.

Modulation of GABA-stimulated chloride influx into membrane vesicles from rat cerebral cortex by triazolobenzodiazepines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obata, T.; Yamamura, H.I.

1988-01-01

The effects of triazolobenzodiazepines of GABA-stimulated /sup 36/Cl/sup -/ uptake by membrane vesicles from rat cerebral cortex were examined. Triazolam and alprazolam showed a significant enhancement of GABA-stimulated /sup 36/Cl/sup -/ uptake at 0.01-10 uM. On the other hand, adinazolam showed a small enhancement at 0.1-1 uM followed by a significant inhibition of GABA-stimulated /sup 36/Cl/sup -/ uptake at 100 uM. The enhancement of GABA-stimulated /sup 36/Cl/sup -/ uptake by 1 uM alprazolam was antagonized by Ro15-1788, a benzodiazepine antagonist, but the inhibition of this response by 30 uM adinazolam was not antagonized by Ro15-1788. These results indicate that triazolobenzodiazepinesmore » enhanced GABA-stimulated /sup 36/Cl/sup -/ uptake through benzodiazepine receptors. High concentrations of adinazolam inhibit GABA-stimulated /sup 36/Cl/sup -/ uptake which may be due to the direct blockade of GABA-gated chloride channel. 23 references, 4 figures.« less

Gallium-67 uptake by the thyroid associated with progressive systemic sclerosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sjoberg, R.J.; Blue, P.W.; Kidd, G.S.

1989-01-01

Although thyroidal uptake of gallium-67 has been described in several thyroid disorders, gallium-67 scanning is not commonly used in the evaluation of thyroid disease. Thyroidal gallium-67 uptake has been reported to occur frequently with subacute thyroiditis, anaplastic thyroid carcinoma, and thyroid lymphoma, and occasionally with Hashimoto's thyroiditis and follicular thyroid carcinoma. A patient is described with progressive systemic sclerosis who, while being scanned for possible active pulmonary involvement, was found incidentally to have abnormal gallium-67 uptake only in the thyroid gland. Fine needle aspiration cytology of the thyroid revealed Hashimoto's thyroiditis. Although Hashimoto's thyroiditis occurs with increased frequency in patientsmore » with progressive systemic sclerosis, thyroidal uptake of gallium-67 associated with progressive systemic sclerosis has not, to our knowledge, been previously described. Since aggressive thyroid malignancies frequently are imaged by gallium-67 scintigraphy, fine needle aspiration cytology of the thyroid often is essential in the evaluation of thyroidal gallium-67 uptake.« less

( sup 3 H)Dopamine uptake by platelet storage granules in schizophrenia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rabey, J.M.; Graff, E.; Oberman, Z.

1992-01-01

({sup 3}H)Dopamine (DA) uptake by platelet storage granules was determined in 26 schizophrenic male patients, paranoid type (14 acute stage; 12 in remission) and 20 age-matched, normal controls. maximum velocity (Vmax) of DA uptake was significantly higher in acute patients, than patients in remission or controls (p>0.05). The apparent Michaelis constant (kM) of DA uptake in acute patients was also significantly different from chronic patients a substantial diminution of DA uptake, while haloperidol produced a substantial diminution of DA uptake, while haloperidol (10{sup {minus}4}, 10{sup {minus}5} M) did not affect the assay. Considering that a DA disequilibrium in schizophrenia maymore » be expressed not only in the brain, but also in the periphery and that an increased amount of DA accumulated in the vesicles, implies that an increased quantity of catecholamine is available for release, our findings suggest additional evidence for the role of DA overactivity in the pathophysiology of this disorder.« less

Genome-wide RNAi screen reveals ALK1 mediates LDL uptake and transcytosis in endothelial cells

PubMed Central

Kraehling, Jan R.; Chidlow, John H.; Rajagopal, Chitra; Sugiyama, Michael G.; Fowler, Joseph W.; Lee, Monica Y.; Zhang, Xinbo; Ramírez, Cristina M.; Park, Eon Joo; Tao, Bo; Chen, Keyang; Kuruvilla, Leena; Larriveé, Bruno; Folta-Stogniew, Ewa; Ola, Roxana; Rotllan, Noemi; Zhou, Wenping; Nagle, Michael W.; Herz, Joachim; Williams, Kevin Jon; Eichmann, Anne; Lee, Warren L.; Fernández-Hernando, Carlos; Sessa, William C.

2016-01-01

In humans and animals lacking functional LDL receptor (LDLR), LDL from plasma still readily traverses the endothelium. To identify the pathways of LDL uptake, a genome-wide RNAi screen was performed in endothelial cells and cross-referenced with GWAS-data sets. Here we show that the activin-like kinase 1 (ALK1) mediates LDL uptake into endothelial cells. ALK1 binds LDL with lower affinity than LDLR and saturates only at hypercholesterolemic concentrations. ALK1 mediates uptake of LDL into endothelial cells via an unusual endocytic pathway that diverts the ligand from lysosomal degradation and promotes LDL transcytosis. The endothelium-specific genetic ablation of Alk1 in Ldlr-KO animals leads to less LDL uptake into the aortic endothelium, showing its physiological role in endothelial lipoprotein metabolism. In summary, identification of pathways mediating LDLR-independent uptake of LDL may provide unique opportunities to block the initiation of LDL accumulation in the vessel wall or augment hepatic LDLR-dependent clearance of LDL. PMID:27869117

Mechanisms of cell uptake, inflammatory potential and protein corona effects with gold nanoparticles.

PubMed

Li, Yang; Monteiro-Riviere, Nancy A

2016-12-01

To assess inflammation, cellular uptake and endocytic mechanisms of gold nanoparticles (AuNP) in human epidermal keratinocytes with and without a protein corona. Human epidermal keratinocytes were exposed to 40 and 80 nm AuNP with lipoic acid, polyethylene glycol (PEG) and branched polyethyleneimine (BPEI) coatings with and without a protein corona up to 48 h. Inhibitors were selected to characterize endocytosis. BPEI-AuNP showed the greatest uptake, while PEG-AuNP had the least. Protein coronas decreased uptake and affected their mechanism. AuNP uptake was energy-dependent, except for 40 nm lipoic-AuNP. Most AuNP were internalized by clathrin and lipid raft-mediated endocytosis, except for 40 nm PEG was by raft/noncaveolae mediated endocytosis. Coronas inhibited caveolae-mediated-endocytosis with lipoic acid and BPEI-AuNP and altered 40 nm PEG-AuNP from raft/noncaveolae to clathrin. Inflammatory responses decreased with a plasma corona. Results suggest protein coronas significantly affect cellular uptake and inflammatory responses of AuNP.

Measurements of nitrogen productivity in the equatorial Pacific

NASA Technical Reports Server (NTRS)

Wilkerson, Frances P.; Dugdale, Richard C.

1992-01-01

During the R/V Wecoma WEC88 cruise that sampled a meridional transect along 150 deg W from 15 deg N to 15 deg S, uptake of nitrate and ammonium by phytoplankton was measured using the stable isotope N-15 with simulated in-situ bottle incubations and shipboard mass spectrometry. A set of 25 daily productivity stations showed the influence of equatorial upwelling on nitrate distribution and N-15 uptake in a band from 6 deg N to 7.5 deg S compared with the oligotrophic waters to the north and south, with the highest values of nitrate uptake occurring at the equator. During a 5-day time series at the equator, there was an increase in nitrate accompanied by increased nitrate uptake. Interestingly, nitrate uptake rates (equivalent to new production rates) at the equator were lower than those predicted by previous investigators. Holdover experiments and uptake versus irradiance curves showed that the phytoplankton was in an early stage of metabolic adaptation and that can be a contributing factor.

Studies on uptake of trivalent and hexavalent chromium by maize (Zea mays).

PubMed

Mishra, S; Singh, V; Srivastava, S; Srivastava, R; Srivastava, M M; Dass, S; Satsangi, G P; Prakash, S

1995-05-01

Pot culture experiments were carried out to study the uptake and translocation of chromium from irrigation water when supplied in its trivalent and hexavalent states to maize plants grown in soil and sand culture. The uptake of chromium was observed to increase with increase in the concentration for both oxidation states of chromium. For the root, the observed order of uptake was CrIII sand > CrVI sand > CrIII soil > CrVI soil, whereas in the lower shoot, upper shoot and fruit the order was CrVI sand > CrVI soil > CrIII sand > CrIII soil. Significantly high uptake of chromium by roots in the sand culture (CrIII treatment) is attributed to the effect of root exudates and degradation products on the mobilization of CrIII. In aerial parts of the plants a higher uptake was observed when the initial supply was CrVI. The trends observed are explained on the basis of the redox behaviour of chromium.

Cyclic variations in nitrogen uptake rate in soybean plants: uptake during reproductive growth

NASA Technical Reports Server (NTRS)

Vessey, J. K.; Raper, C. D. Jr; Henry, L. T.; Raper CD, J. r. (Principal Investigator)

1990-01-01

Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic culture was measured daily during a 63 d period of reproductive development between the first florally inductive photoperiod and [unknown word] seed growth. Removal of NO3- from a replenished solution containing 1.0 mol m-3 NO3- was determined by ion chromatography. Uptake of NO3- continued throughout reproductive development. The net uptake rate of NO3- cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floral stage and about 6 d during the fruiting stage. Coupled with increasing concentrations of carbon and C : N ratios in tissues, the oscillations in net uptake rates of NO3- are evidence that the demand for carbohydrate by reproductive organs is contingent on the availability of nitrogen in the shoot pool rather than that the demand for nitrogen follows the flux of carbohydrate into reproductive tissues.

Iodine-123 metaiodobenzylguanidine imaging of the heart in idiopathic congestive cardiomyopathy and cardiac transplants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glowniak, J.V.; Turner, F.E.; Gray, L.L.

1989-07-01

Iodine-123 metaiodobenzylguanidine ((/sup 123/I)MIBG) is a norepinephrine analog which can be used to image the sympathetic innervation of the heart. In this study, cardiac imaging with (/sup 123/I)MIBG was performed in patients with idiopathic congestive cardiomyopathy and compared to normal controls. Initial uptake, half-time of tracer within the heart, and heart to lung ratios were all significantly reduced in patients compared to normals. Uptake in lungs, liver, salivary glands, and spleen was similar in controls and patients with cardiomyopathy indicating that decreased MIBG uptake was not a generalized abnormality in these patients. Iodine-123 MIBG imaging was also performed in cardiacmore » transplant patients to determine cardiac nonneuronal uptake. Uptake in transplants was less than 10% of normals in the first 2 hr and nearly undetectable after 16 hr. The decreased uptake of MIBG suggests cardiac sympathetic nerve dysfunction while the rapid washout of MIBG from the heart suggests increased cardiac sympathetic nerve activity in idiopathic congestive cardiomyopathy.« less

Escherichia coli K1 utilizes host macropinocytic pathways for invasion of brain microvascular endothelial cells.

PubMed

Loh, Lip Nam; McCarthy, Elizabeth M C; Narang, Priyanka; Khan, Naveed A; Ward, Theresa H

2017-11-01

Eukaryotic cells utilize multiple endocytic pathways for specific uptake of ligands or molecules, and these pathways are commonly hijacked by pathogens to enable host cell invasion. Escherichia coli K1, a pathogenic bacterium that causes neonatal meningitis, invades the endothelium of the blood-brain barrier, but the entry route remains unclear. Here, we demonstrate that the bacteria trigger an actin-mediated uptake route, stimulating fluid phase uptake, membrane ruffling and macropinocytosis. The route of uptake requires intact lipid rafts as shown by cholesterol depletion. Using a variety of perturbants we demonstrate that small Rho GTPases and their downstream effectors have a significant effect on bacterial invasion. Furthermore, clathrin-mediated endocytosis appears to play an indirect role in E. coli K1 uptake. The data suggest that the bacteria effect a complex interplay between the Rho GTPases to increase their chances of uptake by macropinocytosis into human brain microvascular endothelial cells. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Influence of simulated weightlessness on maximal oxygen uptake of untrained rats

NASA Technical Reports Server (NTRS)

Overton, J. Michael; Tipton, Charles M.

1987-01-01

The purpose of this study was to determine the effect of hindlimb suspension on maximal oxygen uptake of rodents. Male Sprague-Dawley rats were assigned to head-down (HD) suspension, horizontal (HOZ) suspension, or cage (C) control for 6-9 days. Rats were tested for maximal oxygen uptake before and after surgical instrumentation (Doppler flow probes, carotid and jugular cannulae), and after suspension. Body weight was significantly decreased after suspension in both HD and HOZ groups, but was significantly increased in the C group. Absolute maximal O2 uptake (ml/min) was not different in the C group. However, because of their increased weight, relative maximal O2 uptake (ml/min per kg) was significantly reduced. In contrast, both relative and absolute maximal O2 uptake were significantly lower, following suspension, for the HD and HOZ groups. These preliminary results support the use of hindlimb suspension as an effective model to study the mechanism(s) of cardiovascular deconditioning.

Organic acids influence iron uptake in the human epithelial cell line Caco-2.

PubMed

Salovaara, Susan; Sandberg, Ann-Sofie; Andlid, Thomas

2002-10-09

It has previously been suggested that organic acids enhance iron absorption. We have studied the effect of nine organic acids on the absorption of Fe(II) and Fe(III) in the human epithelial cell line Caco-2. The effect obtained was dose-dependent, and the greatest increase (43-fold) was observed for tartaric acid (4 mmol/L) on Fe(III) (10 micromol/L). Tartaric, malic, succinic, and fumaric acids enhanced Fe(II) and Fe(III) uptake. Citric and oxalic acid, on the other hand, inhibited Fe(II) uptake but enhanced Fe(III) uptake. Propionic and acetic acid increased the Fe(II) uptake, but had no effect on Fe(III) uptake. Our results show a correlation between absorption pattern and chemical structure; e.g. hydroxyl groups, in addition to carboxyls, were connected with a positive influence. The results may be important for elucidating factors affecting iron bioavailability in the small intestine and for the development of foods with improved iron bioavailability.

Genome-wide RNAi screen reveals ALK1 mediates LDL uptake and transcytosis in endothelial cells.

PubMed

Kraehling, Jan R; Chidlow, John H; Rajagopal, Chitra; Sugiyama, Michael G; Fowler, Joseph W; Lee, Monica Y; Zhang, Xinbo; Ramírez, Cristina M; Park, Eon Joo; Tao, Bo; Chen, Keyang; Kuruvilla, Leena; Larriveé, Bruno; Folta-Stogniew, Ewa; Ola, Roxana; Rotllan, Noemi; Zhou, Wenping; Nagle, Michael W; Herz, Joachim; Williams, Kevin Jon; Eichmann, Anne; Lee, Warren L; Fernández-Hernando, Carlos; Sessa, William C

2016-11-21

In humans and animals lacking functional LDL receptor (LDLR), LDL from plasma still readily traverses the endothelium. To identify the pathways of LDL uptake, a genome-wide RNAi screen was performed in endothelial cells and cross-referenced with GWAS-data sets. Here we show that the activin-like kinase 1 (ALK1) mediates LDL uptake into endothelial cells. ALK1 binds LDL with lower affinity than LDLR and saturates only at hypercholesterolemic concentrations. ALK1 mediates uptake of LDL into endothelial cells via an unusual endocytic pathway that diverts the ligand from lysosomal degradation and promotes LDL transcytosis. The endothelium-specific genetic ablation of Alk1 in Ldlr-KO animals leads to less LDL uptake into the aortic endothelium, showing its physiological role in endothelial lipoprotein metabolism. In summary, identification of pathways mediating LDLR-independent uptake of LDL may provide unique opportunities to block the initiation of LDL accumulation in the vessel wall or augment hepatic LDLR-dependent clearance of LDL.

Glucose uptake in rat soleus - Effect of acute unloading and subsequent reloading

NASA Technical Reports Server (NTRS)

Henriksen, Eric J.; Tischler, Marc E.

1988-01-01

The effect of acutely reduced weight bearing (unloading) on the in vitro uptake of 2-1,2-H-3-deoxy-D-glucose was studied in the soleus muscle by tail casting and suspending rats. After just 4 h, the uptake of 2-deoxy-D-glucose fell (-19 percent) and declined further after an additional 20 h of unloading. This diminution at 24 h was associated with slower oxidation of C-14-glucose and incorporation of C-14-glucose into glycogen. At 3 days of unloading, basal uptake of 2-deoxy-D-glucose did not differ from control. Reloading of the soleus after 1 or 3 days of unloading increased uptake of 2-deoxy-D-glucose above control and returned it to normal within 6 h and 4 days, respectively. These effects of unloading and recovery were caused by local changes in the soleus, because the extensor digitorum longus from the same hindlimbs did not display any alterations in uptake of 2-deoxy-D-glucose or metabolism of glucose.

Anorectic activities of serotonin uptake inhibitors: correlation with their potencies at inhibiting serotonin uptake in vivo and /sup 3/H-mazindol binding in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angel, I.; Taranger, M.A.; Claustre, Y.

1988-01-01

The mechanism of anorectic action of several serotonin uptake inhibitors was investigated by comparing their anorectic potencies with several biochemical and pharmacological properties and in reference to the novel compound SL 81.0385. The anorectic effect of the potent serotonin uptake inhibitor SL 81.0385 was potentiated by pretreatment with 5-hydroxytryptophan and blocked by the serotonin receptor antagonist metergoline. A good correlation was obtained between the ED/sub 50/ values of anorectic action and the ED/sub 50/ values of serotonin uptake inhibition in vivo (but not in vitro) for several specific serotonin uptake inhibitors. Most of the drugs tested displaced (/sup 3/H)-mazindol frommore » its binding to the anorectic recognition site in the hypothalamus, except the pro-drug zimelidine which was inactive. Excluding zimelidine, a good correlation was obtained between the affinities of these drugs for (/sup 3/H)-mazindol binding and their anorectic action indicating that their anorectic activity may be associated with an effect mediated through this site. Taken together these results suggest that the anorectic action of serotonin uptake inhibitors is directly associated to their ability to inhibit serotonin uptake and thus increasing the synaptic levels of serotonin. The interactions of these drugs with the anorectic recognition site labelled with (/sup 3/H)-mazindol is discussed in connection with the serotonergic regulation of carbohydrate intake.« less

Elucidating the mechanisms of nickel compound uptake: A review of particulate and nano-nickel endocytosis and toxicity

PubMed Central

Muñoz, Alexandra; Costa, Max

2012-01-01

Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses - most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980’s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanism of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties. PMID:22206756

Market uptake of orphan drugs--a European analysis.

PubMed

Picavet, E; Annemans, L; Cleemput, I; Cassiman, D; Simoens, S

2012-12-01

Variations in market uptake of an orphan drug have important implications with respect to access to care and inequality of treatment. Therefore, the aim of this study was to quantify both the sales and volume uptake of orphan drugs in Europe and to assess whether a country's gross domestic product (GDP) and/or health technology assessment (HTA) influences the orphan drugs' market uptake. We analysed the numbers of orphan drugs launched and the sales and volume uptake for 17 orphan drugs in 23 European countries from 2001 until the beginning of 2010 using the IMS Health database. Countries were clustered based on GDP and the availability of a formal HTA-organization. The uptake of orphan drugs varied across European countries. The highest volumes and contributions of orphan drugs in the first year occurred in countries with a high GDP (and implicitly, a higher budget for healthcare), independently of the existence of an HTA-organization. In contrast, in countries with a low GDP, orphan drugs were less available when there was a formal HTA-organization. There, budgetary restrictions can cause the exclusion of less cost-effective orphan drugs. We observed substantial variation in the market uptake of orphan drugs. Such variation may have important implications with respect to access to care and inequality of treatment. The uptake of orphan drugs could be promoted through the clinical added value of orphan drugs (CAVOD) project and various conditional pricing and reimbursement mechanisms. © 2012 Blackwell Publishing Ltd.

Leaf and stem CO/sub 2/ uptake in the three subfamilies of the Cactaceae. [Pereskia aculeata; Pereskia grandifolia; Maihuenia poeppigii; Carnegiea gigantea; Ferocactus acanthodes; Coryphantha vivipara; Mammillaria dioica; Opuntia ficus-inidica; Pereskiopsis porteri; Quiabentia chacoensis; Austrocylindropuntia subulata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nobel, P.S.; Hartsock, T.L.

Net CO/sub 2/ uptake over 24-hour periods was examined for the leaves and for the stems of 11 species of cacti representing all three subfamilies. For Pereskia aculeata, Pereskia grandifolia, and Maihuenia poeppigii (subfamily Pereskioideae), all the net shoot CO/sub 2/ uptake was by the leaves and during the daytime. In contrast, for the leafless species Carnegiea gigantea, Ferocactus acanthodes, Coryphantha vivipara, and Mammillaria dioica (subfamily Cactoideae), all the shoot net CO/sub 2/ uptake was by the stems and at night. Similarly, for leafless Opuntia ficus-indica (subfamily Opuntioideae), all net CO/sub 2/ uptake occurred at night. For leafy members ofmore » the Opuntioideae (Pereskiopsis porteri, Quiabentia chacoensis, Austrocylindropuntia subulata), at least 88% of the shoot CO/sub 2/ uptake over 24 hours was by the leaves and some CO/sub 2/ uptake occurred at night. Leaves responded to the instantaneous level of photosynthetically active radiation (PAR) during the daytime, as occurs for C/sub 3/ plants, whereas nocturnal CO/sub 2/ uptake by stems of O. ficus-indica and F. acanthodes responded to the total daily PAR, as occurs for Crassulacean acid metabolism (CAM) plants. Thus, under the well-watered conditions employed, the Pereskioideae behaved as C/sub 3/ plants, the Cactoideae behaved as CAM plants, and the Opuntioideae exhibited characteristics of both pathways.« less

Molecular and cellular characterisation of the zinc uptake (Znu) system of Nostoc punctiforme.

PubMed

Hudek, Lee; Pearson, Leanne A; Michalczyk, Agnes; Neilan, Brett A; Ackland, M Leigh

2013-11-01

Metal homoeostasis in cyanobacteria is based on uptake and export systems that are controlled by their own regulators. This study characterises the zinc uptake (Znu) system in Nostoc punctiforme. The system was found to comprise of three subunits in an ACB operon: a Zn(2+)-binding protein (ZnuA18), a transmembrane domain (ZnuB) and an ATPase (ZnuC). These proteins are encoded within the znu operon regulated by a zinc uptake transcription repressor (Zur). Interestingly, a second Zn(2+)-binding protein (ZnuA08) was also identified at a distal genomic location. Interactions between components of the ZnuACB system were investigated using knockouts of the individual genes. The znuA08(-), znuA18(-), znuB(-) and znuC(-) mutants displayed overall reduced znuACB transcript levels, suggesting that all system components are required for normal expression of znu genes. Zinc uptake assays in the Zn(2+)-binding protein mutant strains showed that the disruption of znuA18 had a greater negative effect on zinc uptake than disruption of znuA08. Complementation studies in Escherichia coli indicated that both znuA08 and znuA18 were able to restore zinc uptake in a znuA(-) mutant, with znuA18 permitting the highest zinc uptake rate. The N. punctiforme zur was also able to complement the E. coli zur(-) mutant. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Effects of the Monoamine Uptake Inhibitors RTI-112 and RTI-113 on Cocaine- and Food-Maintained Responding in Rhesus Monkeys

PubMed Central

SS, Negus; NK, Mello; HL, Kimmel; LL, Howell; FI, Carroll

2009-01-01

Cocaine blocks uptake of the monoamines dopamine, serotonin and norepinephrine, and monoamine uptake inhibitors constitute one class of drugs under consideration as candidate “agonist” medications for the treatment of cocaine abuse and dependence. The pharmacological selectivity of monoamine uptake inhibitors to block uptake of dopamine, serotonin and norepinephrine is one factor that may influence the efficacy and/or safety of these compounds as drug abuse treatment medications. To address this issue, the present study compared the effects of 7-day treatment with a non-selective monoamine uptake inhibitor (RTI-112) and a dopamine-selective uptake inhibitor (RTI-113) on cocaine- and food-maintained responding in rhesus monkeys. Monkeys (N=3) were trained to respond for cocaine injections (0.01 mg/kg/inj) and food pellets under a second-order schedule [FR2(VR16:S)] during alternating daily components of cocaine and food availability. Both RTI-112 (0.0032–0.01 mg/kg/hr) and RTI-113 (0.01–0.056 mg/kg/hr) produced dose-dependent, sustained and nearly complete elimination of cocaine self-administration. However, for both drugs, the potency to reduce cocaine self-administration was similar to the potency to reduce food-maintained responding. These findings do not support the hypothesis that pharmacological selectivity to block dopamine uptake is associated with behavioral selectivity to decrease cocaine- vs. food-maintained responding in rhesus monkeys. PMID:18755212

Water uptake by two river red gum ( Eucalyptus camaldulensis) clones in a discharge site plantation in the Western Australian wheatbelt

NASA Astrophysics Data System (ADS)

Marshall, John K.; Morgan, Anne L.; Akilan, Kandia; Farrell, Richard C. C.; Bell, David T.

1997-12-01

The heat-pulse technique was used to estimate year-long water uptake in a discharge zone plantation of 9-year-old clonal Eucalyptus camaldulensis Dehnh. near Wubin, Western Australia. Water uptake matched rainfall closely during weter months but exceeded rainfall as the dry season progressed. Average annual water uptake (1148 mm) exceeded rainfall (432 mm) by about 2.7 fold and approached 56% of pan evaporation for the area. The data suggest that at least 37% (i.e. ( {1}/{2.7}) × 100 ) of the lower catchment discharge zone should be planted to prevent the rise of groundwater. Water uptake varied with soil environment, season and genotype. Upslope trees used more water than did downslope trees. Water uptake was higher in E. camaldulensis clone M80 than in clone M66 until late spring. The difference reversed as summer progressed. Both clones, however, have the potential to dry out the landscape when potential evapotranspiration exceeds rainfall. This variation in water uptake within the species indicates the potential for manipulating plantation uptake by matching tree characteristics to site characteristics. Controlled experiments on the heat-pulse technique indicated accuracy errors of approximately 10%. This, combined with the ability to obtain long-term, continuous data and the superior logistics of use of the heat-pulse technique, suggests that results obtained by it would be much more reliable than those achieved by the ventilated chamber technique.

Diurnal changes in net uptake rate of nitrate are associated with changes in estimated export of carbohydrates to roots

NASA Technical Reports Server (NTRS)

Rideout, J. W.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

1994-01-01

The rate of NO3- uptake by soybean (Glycine max [L.] Merrill) roots generally declines during the night in association with progressive depletion of the nonstructural carbohydrate pool in the shoot as well as the concentration of carbohydrates in roots. To determine if NO3- uptake rate changes in response to variations in translocation rate of carbohydrates from shoot to roots per se or to carbohydrate status of the roots, the night period was interrupted with a low light level from incandescent lamps to alter the diurnal pattern of NO3- uptake by roots and export of carbohydrate from shoots of nonnodulated soybean. Depletion of NO3- from replenished, complete nutrient solutions containing 1 mM NO3- was measured by ion chromatography and rates of NO3- uptake were calculated. Changes in export of carbohydrates from shoot to roots during intervals of the night period were calculated as the differences between rates of disappearance in contents of nonstructural carbohydrates and their estimated rates of utilization in shoot respiration and growth. A positive, significant correlation occurred between changes in calculated rates of carbohydrate export from shoots and NO3- uptake rates. Conversely, there was no significant correlation between concentrations of nonstructural carbohydrates in roots and NO3- uptake rates. These results support the hypothesis that carbohydrate flux from shoot to roots has a direct role in regulation of nitrogen uptake by the whole plant.

Elucidating the mechanisms of nickel compound uptake: A review of particulate and nano-nickel endocytosis and toxicity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muñoz, Alexandra; Costa, Max, E-mail: Max.Costa@nyumc.org

Nickel (Ni) is a worldwide pollutant and contaminant that humans are exposed to through various avenues resulting in multiple toxic responses — most alarming is its clear carcinogenic nature. A variety of particulate Ni compounds persist in the environment and can be distinguished by characteristics such as solubility, structure, and surface charge. These characteristics influence cellular uptake and toxicity. Some particulate forms of Ni are carcinogenic and are directly and rapidly endocytized by cells. A series of studies conducted in the 1980s observed this process, and we have reanalyzed the results of these studies to help elucidate the molecular mechanismmore » of particulate Ni uptake. Originally the process of uptake observed was described as phagocytosis, however in the context of recent research we hypothesize that the process is macropinocytosis and/or clathrin mediated endocytosis. Primary considerations in determining the route of uptake here include calcium dependence, particle size, and inhibition through temperature and pharmacological approaches. Particle characteristics that influenced uptake include size, charge, surface characteristics, and structure. This discussion is relevant in the context of nanoparticle studies and the emerging interest in nano-nickel (nano-Ni), where toxicity assessments require a clear understanding of the parameters of particulate uptake and where establishment of such parameters is often obscured through inconsistencies across experimental systems. In this regard, this review aims to carefully document one system (particulate nickel compound uptake) and characterize its properties.« less

Systematic review of the effect of immunization mandates on uptake of routine childhood immunizations.

PubMed

Lee, Cecilia; Robinson, Joan L

2016-06-01

The efficacy of immunization mandates for childcare or school entry is a long-standing controversy. The United States (US) adopted school entry immunization mandates in the 1800s, while most countries still do not have mandates. The objective of this systematic review was to analyze the evidence that immunization uptake increases with mandates. A search was conducted for studies that compared immunization uptake in a population prior to and after mandates, or in similar populations with one group having and the other not having mandates. Data were extracted and synthesized qualitatively due to the heterogeneity of study design. Eleven before-and-after studies and ten studies comparing uptake in similar populations with and without mandates were included. Studies were from the US (n = 18), France (n = 1) and Canada (n = 2). Eleven of the 21 studies looked at middle school mandates. All but two studies showed at least a trend towards increased uptake with mandates. Higher uptake was associated with a more long-standing mandate. Immunization mandates have generally led to increased short-term and long-term uptake in the group to whom the mandate applies. Many studies have centered around middle school mandates in the US and there is a paucity of studies of childcare mandates or of studies of mandates in other countries or in settings with relatively high baseline immunization uptake. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Improving prediction of metal uptake by Chinese cabbage (Brassica pekinensis L.) based on a soil-plant stepwise analysis.

PubMed

Zhang, Sha; Song, Jing; Gao, Hui; Zhang, Qiang; Lv, Ming-Chao; Wang, Shuang; Liu, Gan; Pan, Yun-Yu; Christie, Peter; Sun, Wenjie

2016-11-01

It is crucial to develop predictive soil-plant transfer (SPT) models to derive the threshold values of toxic metals in contaminated arable soils. The present study was designed to examine the heavy metal uptake pattern and to improve the prediction of metal uptake by Chinese cabbage grown in agricultural soils with multiple contamination by Cd, Cu, Ni, Pb, and Zn. Pot experiments were performed with 25 historically contaminated soils to determine metal accumulation in different parts of Chinese cabbage. Different soil bioavailable metal fractions were determined using different extractants (0.43M HNO3, 0.01M CaCl2, 0.005M DTPA, and 0.01M LWMOAs), soil moisture samplers, and diffusive gradients in thin films (DGT), and the fractions were compared with shoot metal uptake using both direct and stepwise multiple regression analysis. The stepwise approach significantly improved the prediction of metal uptake by cabbage over the direct approach. Strongly pH dependent or nonlinear relationships were found for the adsorption of root surfaces and in root-shoot uptake processes. Metals were linearly translocated from the root surface to the root. Therefore, the nonlinearity of uptake pattern is an important explanation for the inadequacy of the direct approach in some cases. The stepwise approach offers an alternative and robust method to study the pattern of metal uptake by Chinese cabbage (Brassica pekinensis L.). Copyright © 2016. Published by Elsevier B.V.

Rifampicin Lipid-Polymer hybrid nanoparticles (LIPOMER) for enhanced Peyer's patch uptake.

PubMed

Bachhav, Sagar S; Dighe, Vikas D; Kotak, Darsheen; Devarajan, Padma V

2017-10-30

The oral uptake of intact nanocarriers through Peyer's patches is an important uptake pathway. We report Rifampicin Lipid-Polymer hybrid nanoparticles (RIF-LIPOMER) using glyceryl monostearate as lipid and the mucoadhesive polymer, Gantrez, with the objective of balancing hydrophobicity and mucoadhesion for enhanced Peyer's patch uptake. RIF-LIPOMER was optimized for size, hydrophobicity, and mucoadhesion using Box-Behnken. Designed RIF-LIPOMER (RIF-LIPO-120) exhibited average particle size in the range 300-400nm with drug loading >12%. DSC and XRD confirmed complete amorphization. Contact angle and mucoadhesion force revealed that RIF-LIPO-120 exhibited greater hydrophobicity and lower mucoadhesion compared to Gantrez nanoparticles (RIF-GzNP). Comparative uptake of fluorescent labelled RIF-LIPO-120 and RIF-GzNP, through Peyer's patch following intraduodenal administration in rats, revealed the high accumulation of RIF-GzNP at the villi border, and high Peyer's patch uptake of RIF-LIPO-120. Furthermore, lower accumulation of RIF-LIPO-120 in the liver, compared to RIF-GzNP, suggested bypass of the portal circulation and lymphatic uptake through Peyer's patches. Significantly higher lung: plasma concentration ratio exhibited by RIF-LIPO-120 compared to RIF-GzNP confirmed the same (p<0.05). Our study demonstrated that optimization of hydrophobicity and mucoadhesion of nanoparticles could favor Peyer's patch uptake, which in turn could enable enhanced drug accumulation in the lungs with advantage in the therapy of pulmonary afflictions. Copyright © 2017 Elsevier B.V. All rights reserved.

Thromboxane plays a role in postprandial jejunal oxygen uptake and capillary exchange.

PubMed

Alemayehu, A; Chou, C C

1990-09-01

The effects of a thromboxane A2 (TxA2)-endoperoxide receptor antagonist, SQ 29548, on jejunal blood flow, oxygen uptake, and capillary filtration coefficient (Kfc) were determined in anesthetized dogs under resting conditions and during the presence of predigested food in the jejunal lumen in three series of experiments. In series 1, 2.0 micrograms intra-arterial administration of SQ 29548 was found to abolish completely the vasoconstrictor action of graded doses (0.05-2.0 micrograms) of intra-arterial injection of a TxA2-endoperoxide analogue, U44069. SQ 29548 (2.0 micrograms ia) per se did not significantly alter resting jejunal blood flow, oxygen uptake, capillary pressure, or Kfc. Before SQ 29548, placement of food plus bile into the jejunal lumen increased blood flow +42 +/- 9%, oxygen uptake +28 +/- 7%, and Kfc +24 +/- 6%. After SQ 29548, the food placement increased blood flow +37 +/- 8%, oxygen uptake +52 +/- 11%, and Kfc +63 +/- 20%. The food-induced increases in oxygen uptake and Kfc after SQ 29548 were significantly greater than those induced before the blocking of TxA2-endoperoxide receptors by SQ 29548. Our study indicates that endogenous thromboxane does not play a role in regulating jejunal blood flow, capillary filtration, and oxygen uptake under resting conditions. However, it plays a role in limiting the food-induced increases in jejunal oxygen uptake and capillary exchange capacity without influencing the food-induced hyperemia.

Tryptophanyl-tRNA synthetase mediates high-affinity tryptophan uptake into human cells.

PubMed

Miyanokoshi, Miki; Yokosawa, Takumi; Wakasugi, Keisuke

2018-06-01

The tryptophan (Trp) transport system has a high affinity and selectivity toward Trp, and has been reported to exist in both human and mouse macrophages. Although this system is highly expressed in interferon-γ (IFN-γ)-treated cells and indoleamine 2,3-dioxygenase 1 (IDO1)-expressing cells, its identity remains incompletely understood. Tryptophanyl-tRNA synthetase (TrpRS) is also highly expressed in IFN-γ-treated cells and also has high affinity and selectivity for Trp. Here, we investigated the effects of human TrpRS expression on Trp uptake into IFN-γ-treated human THP-1 monocytes or HeLa cells. Inhibition of human TrpRS expression by TrpRS-specific siRNAs decreased and overexpression of TrpRS increased Trp uptake into the cells. Of note, the TrpRS-mediated uptake system had more than hundred-fold higher affinity for Trp than the known System L amino acid transporter, promoted uptake of low Trp concentrations, and had very high Trp selectivity. Moreover, site-directed mutagenesis experiments indicated that Trp- and ATP-binding sites, but not tRNA-binding sites, in TrpRS are essential for TrpRS-mediated Trp uptake into the human cells. We further demonstrate that the addition of purified TrpRS to cell culture medium increases Trp uptake into cells. Taken together, our results reveal that TrpRS plays an important role in high-affinity Trp uptake into human cells. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Nitrogen uptake by the shoots of smooth cordgrass Spartina alterniflora

USGS Publications Warehouse

Mozdzer, T.J.; Kirwan, M.; McGlathery, K.J.; Zieman, J.C.

2011-01-01

The smooth cordgrass Spartina alterniflora is the foundation species in intertidal salt marshes of the North American Atlantic coast. Depending on its elevation within the marsh, S. alterniflora may be submerged for several hours per day. Previous ecosystem-level studies have demonstrated that S. alterniflora marshes are a net sink for nitrogen (N), and that removal of N from flooding tidal water can provide enough N to support the aboveground biomass. However, studies have not specifically investigated whether S. alterniflora plants assimilate nutrients through their aboveground tissue. We determined in situ foliar and stem N uptake kinetics for 15NH4, 15NO3, and 15N-glycine by artificially flooding plants in a mid-Atlantic salt marsh. To determine the ecological importance of shoot uptake, a model was created to estimate the time of inundation of S. alterniflora in 20 cm height intervals during the growing season. Estimates of inundation time, shoot mass, N uptake rates, and N availability from long-term data sets were used to model seasonal shoot N uptake. Rates of aboveground N uptake rates (leaves + stems) were ranked as follows: NH4+ > glycine > NO3–. Our model suggests that shoot N uptake may satisfy up to 15% of the growing season N demand in mid-Atlantic salt marshes, with variation depending on plant elevation and water column N availability. However, in eutrophic estuaries, our model indicates the potential of the plant canopy as a nutrient filter, with shoot uptake contributing 66 to 100% of plant N demand.

Lesion-induced plasticity of high affinity choline uptake in the developing rat fascia dentata.

PubMed

Nadler, J V; Shelton, D L; Cotman, C W

1979-03-23

After removal of the perforant path input to the rat fascia dentata at the age of 11 days, cholinergic septohippocampal fibers invade the denervated area. We have examined the effect of this lesion on hemicholinium-sensitive, high affinity choline uptake and its coupling to acetylcholine synthesis, specific properties of the septohippocampal input. Removal of the ipsilateral perforant path fibers increased the velocity of high affinity choline uptake by dentate particulate preparations, usually within 1 day. Studies conducted 5--104 days after operation showed a consistent 50--65% elevation in the molecular (denervated) layer. In contrast, the choline uptake rate in the granular layer eventually decreased slightly. Calculation of choline uptake rates independently of protein (per whole region) revealed that fasciae dentatae from operated and control sides accumulated choline at approximately equal rates, but on the operated side a greater percentage was transported by structures from the molecular layer and a lesser percentage by those from the granular layer. The rate of acetylcholine synthesis from exogenous choline increased to the same extent as high affinity choline uptake from 3 days after operation onwards. The changes in high affinity choline uptake and acetylcholine synthesis coincided spatially and temporally with the reactive growth of septohippocampal fibers. Our results support the view that a perforant path lesion during development permanently alters the distribution of functional septohippocampal boutons in the fascia dentata. Acetylcholine synthesis is regulated to the same extent by high affinity choline uptake in the anomalous boutons as in normally located boutons.

Glucocorticoid deprivation alters in vivo glucose uptake by muscle and adipose tissues of GTG-obese mice.

PubMed

Blair, S C; Caterson, I D; Cooney, G J

1995-11-01

The effect of 1 wk of glucocorticoid deprivation by surgical adrenalectomy (ADX) on tissue 2-deoxy(-)[U-14C]glucose (2-DG) uptake and hepatic glucose production (HGP) was assessed in conscious, catheterized mice 5 wk after the induction of obesity with gold thioglucose (GTG). Despite the prevailing hyperglycemia and hyperinsulinemia, glucose uptake by heart, quadriceps muscle, and interscapular brown adipose tissue (BAT) of GTG-obese mice was unchanged compared with controls, suggesting that the hyperglycemia of GTG-obese mice is able to compensate for the insulin resistance of these tissues. In contrast, epididymal white adipose tissue (WAT) of GTG-obese mice showed increased glucose uptake with hyperglycemia and hyperinsulinemia. ADX decreased the hyperglycemia and lowered the elevated glycogen content of the liver of GTG-obese mice. ADX reduced glucose uptake by heart and WAT of control and GTG-obese mice, consistent with the concomitant decrease in insulinemia. Glucose uptake by muscle of control and GTG-obese mice was not significantly decreased after ADX despite the decrease in insulin, and ADX increased glucose uptake by BAT of GTG-obese mice, suggesting increased sympathetically mediated thermogenesis in this tissue. HGP was increased in GTG-obese mice compared with controls, and ADX significantly reduced HGP in both GTG-obese and control mice. These results suggest that the improved glucose tolerance of ADX GTG-obese mice and ADX control mice is due to a decrease in HGP rather than an increase in peripheral glucose uptake.

Season and application rates affect vaccine bait consumption by prairie dogs in Colorado and Utah, USA

USGS Publications Warehouse

Tripp, Daniel W.; Rocke, Tonie E.; Streich, Sean P.; Brown, Nathanael L.; Fernandez, Julia Rodriguez-Ramos; Miller, Michael W.

2014-01-01

Plague, a zoonotic disease caused by the bacterium Yersinia pestis, causes high rates of mortality in prairie dogs (Cynomys spp.). An oral vaccine against plague has been developed for prairie dogs along with a palatable bait to deliver vaccine and a biomarker to track bait consumption. We conducted field trials between September 2009 and September 2012 to develop recommendations for bait distribution to deliver plague vaccine to prairie dogs. The objectives were to evaluate the use of the biomarker, rhodamine B, in field settings to compare bait distribution strategies, to compare uptake of baits distributed at different densities, to assess seasonal effects on bait uptake, and to measure bait uptake by nontarget small mammal species. Rhodamine B effectively marked prairie dogs' whiskers during these field trials. To compare bait distribution strategies, we applied baits around active burrows or along transects at densities of 32, 65, and 130 baits/ha. Distributing baits at active burrows or by transect did not affect uptake by prairie dogs. Distributing baits at rates of ≥65/ha (or ≥1 bait/active burrow) produced optimal uptake, and bait uptake by prairie dogs in the autumn was superior to uptake in the spring. Six other species of small mammals consumed baits during these trials. All four species of tested prairie dogs readily consumed the baits, demonstrating that vaccine uptake will not be an obstacle to plague control via oral vaccination.

Economic and Social Impact of Increasing Uptake of Cardiac Rehabilitation Services--A Cost Benefit Analysis.

PubMed

De Gruyter, Elaine; Ford, Greg; Stavreski, Bill

2016-02-01

Cardiac rehabilitation can reduce mortality, improve cardiac risk factor profile and reduce readmissions; yet uptake remains low at 30%. This research aims to investigate the social and economic impact of increasing the uptake of cardiac rehabilitation in Victoria, Australia using cost benefit analysis (CBA). Cost benefit analysis has been undertaken over a 10-year period to analyse three scenarios: (1) Base Case: 30% uptake; (2) Scenario 1: 50% uptake; and (3) Scenario 2: 65% uptake. Impacts considered include cardiac rehabilitation program costs, direct inpatient costs, other healthcare costs, burden of disease, productivity losses, informal care costs and net deadweight loss. There is a net financial saving of $46.7-$86.7 million under the scenarios. Compared to the Base Case, an additional net benefit of $138.9-$227.2 million is expected. This results in a Benefit Cost Ratio of 5.6 and 6.8 for Scenarios 1 and 2 respectively. Disability Adjusted Life Years were 21,117-37,565 years lower than the Base Case. Greater uptake of cardiac rehabilitation can reduce the burden of disease, directly translating to benefits for society and the economy. This research supports the need for greater promotion, routine referral to be made standard practice and implementation of reforms to boost uptake. Copyright © 2015 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

( sup 99m Tc)diphosphonate uptake and hemodynamics in arthritis of the immature dog knee

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, E.S.; Soballe, K.; Henriksen, T.B.

1991-03-01

The relationship between (99mTc)diphosphonate uptake and bone hemodynamics was studied in canine carrageenan-induced juvenile chronic arthritis. Blood flow was determined with microspheres, plasma and red cell volumes were measured by labeled fibrinogen and red cells, and the microvascular volume and mean transit time of blood were calculated. Normal femoral epiphyses had lower central and higher subchondral blood flow and diphosphonate uptake values. Epiphyseal vascular volume was uniform, resulting in a greater transit time of blood centrally. In arthritis, blood flow and diphosphonate uptake were increased subchondrally and unaffected centrally, while epiphyseal vascular volume was increased throughout, leading to prolonged transitmore » time centrally. The normal metaphyses had low blood flow and diphosphonate uptake values in cancellous bone and very high values in growth plates, but a large vascular volume throughout. The mean transit time therefore was low in growth plates and high in adjacent cancellous bone. Arthritis caused decreased blood flow and diphosphonate uptake in growth plates but increased vascular volume and transit time of blood. Diphosphonate uptake correlated positively with blood flow and plasma volume and negatively with red cell volume in a nonlinear fashion. Thus, changes in diphosphonate uptake and microvascular hemodynamics occur in both epiphyseal and metaphyseal bone in chronic synovitis of the immature knee. The (99mTc)diphosphonate bone scan seems to reflect blood flow, plasma volume, and red cell volume of bone.« less

Exercise-induced muscle glucose uptake in mice with graded, muscle-specific GLUT-4 deletion

PubMed Central

Howlett, Kirsten F; Andrikopoulos, Sofianos; Proietto, Joseph; Hargreaves, Mark

2013-01-01

To investigate the importance of the glucose transporter GLUT-4 for muscle glucose uptake during exercise, transgenic mice with skeletal muscle GLUT-4 expression approximately 30–60% of normal (CON) and approximately 5–10% of normal (KO) were generated using the Cre/Lox system and compared with wild-type (WT) mice during approximately 40 min of treadmill running (KO: 37.7 ± 1.3 min; WT: 40 min; CON: 40 min, P = 0.18). In WT and CON animals, exercise resulted in an overall increase in muscle glucose uptake. More specifically, glucose uptake was increased in red gastrocnemius of WT mice and in the soleus and red gastrocnemius of CON mice. In contrast, the exercise-induced increase in muscle glucose uptake in all muscles was completely abolished in KO mice. Muscle glucose uptake increased during exercise in both red and white quadriceps of WT mice, while the small increases in CON mice were not statistically significant. In KO mice, there was no change at all in quadriceps muscle glucose uptake. No differences in muscle glycogen use during exercise were observed between any of the groups. However, there was a significant increase in plasma glucose levels after exercise in KO mice. The results of this study demonstrated that a reduction in skeletal muscle GLUT-4 expression to approximately 10% of normal levels completely abolished the exercise-induced increase in muscle glucose uptake. PMID:24303141

Membrane transport mechanisms of choline in human intestinal epithelial LS180 cells.

PubMed

Horie, Asuka; Ishida, Kazuya; Watanabe, Yuri; Shibata, Kaito; Hashimoto, Yukiya

2014-12-01

The aim of the present study was to investigate the membrane transport mechanisms of choline using human intestinal epithelial LS180 cells. The mRNA of choline transporter-like proteins (CTLs) was expressed significantly in LS180 cells, and the rank order was CTL1 > CTL4 > CTL3 > CTL2 > CTL5. In contrast, the mRNA expression of other choline transporters, organic cation transporter (OCT) 1, OCT2 and high-affinity choline transporter 1 (CHT1), was considerably lower in LS180 cells. Five mm unlabelled choline, hemicolinium-3 and guanidine, but not tetraethylammonium, inhibited the cellular uptake of 100 µm choline in LS180 cells. The uptake of choline into LS180 cells was virtually Na(+)-independent. The uptake of choline was significantly decreased by acidification of the extracellular pH; however, it was not increased by alkalization of the extracellular pH. In addition, both acidification and alkalization of intracellular pH decreased the uptake of choline, indicating that the choline uptake in LS180 cells is not stimulated by the outward H(+) gradient. On the other hand, the uptake of choline was decreased by membrane depolarization along with increasing extracellular K(+) concentration. In addition, the Na(+)-independent uptake of choline was saturable, and the Km value was estimated to be 108 µm. These findings suggest that the uptake of choline into LS180 cells is membrane potential-dependent, but not outward H(+) gradient-dependent. Copyright © 2014 John Wiley & Sons, Ltd.

Cinnamon water extracts increase glucose uptake but inhibit adiponectin secretion in 3T3-L1 adipose cells.

PubMed

Roffey, Benjamin; Atwal, Avtar; Kubow, Stan

2006-08-01

The effects of three concentrations (0.2, 0.3, and 0.4 mg/mL) of a cinnamon extract (CE) (Cinnamomum zeylanicum) on glucose uptake and adiponectin secretion in 3T3-L1 adipocytes were examined in the presence and absence of 0.5 nM and 50 nM insulin. In the absence of insulin, adipocytes exposed to 0.2 mg/mL CE showed an approximate two-fold increase in glucose uptake relative to controls although glucose uptake was unaffected by the two higher concentrations of CE. No effect of CE on glucose uptake was noted in the presence of 0.5 nM insulin whereas the two highest concentrations (0.3 and 0.4 mg/mL) of CE showed a significant dose-dependent decrease in glucose uptake in the presence of 50 nM insulin. Treatment of the adipocytes with 50 nM wortmannin, an irreversible inhibitor of the p110 isoform of phosphoinositide 3'-kinase, was associated with complete inhibition of the stimulated glucose uptake induced by 0.2 mg/mL CE. Treatment of the adipocytes with 0.2 mg/mL CE was associated with an inhibition of adiponectin secretion to levels that were nondetectable. The present study indicates that although 0.2 mg/mL CE has insulin-mimetic action in 3T3-adipocytes in terms of glucose uptake, secretion of the antidiabetic hormone adiponectin is adversely affected.

Nutrient uptake of peanut genotypes under different water regimes

USDA-ARS?s Scientific Manuscript database

Drought is a serious environmental stress limiting growth and productivity in peanut and other crops. Nutrient uptake of peanut is reduced under drought conditions, which reduces yield. The objectives of this study were to investigate nutrient uptake of peanut genotypes in response to drought and ...

Bark water uptake promotes localized hydraulic recovery in coastal redwood crown

USDA-ARS?s Scientific Manuscript database

Coastal redwood (Sequoia sempervirens), the world’s tallest tree species, rehydrates leaves via foliar water uptake during fog/rain events. Here we examine if bark also permits water uptake in redwood branches, along with potential flow mechanisms and biological significance. Using isotopic labeling...

The effects of temperature and salinity on 17-α-ethynylestradiol uptake and its relationship to oxygen consumption in the model euryhaline teleost (Fundulus heteroclitus).

PubMed

Blewett, Tamzin; MacLatchy, Deborah L; Wood, Chris M

2013-02-01

The synthetic estrogen 17-α-ethynylestradiol (EE2), a component of birth control and hormone replacement therapy, is discharged into the environment via wastewater treatment plant (WWTP) effluents. The present study employed radiolabeled EE2 to examine impacts of temperature and salinity on EE2 uptake in male killifish (Fundulus heteroclitus). Fish were exposed to a nominal concentration of 100ng/L EE2 for 2h. The rate of EE2 uptake was constant over the 2h period. Oxygen consumption rates (MO(2)), whole body uptake rates, and tissue-specific EE2 distribution were determined. In killifish acclimated to 18°C at 16ppt (50% sea water), MO(2) and EE2 uptake were both lower after 24h exposure to 10°C and 4°C, and increased after 24h exposure to 26°C. Transfer to fresh water (FW) for 24h lowered EE2 uptake rate, and long-term acclimation to fresh water reduced it by 70%. Both long-term acclimation to 100% sea water (32ppt) and a 24h transfer to 100% sea water also reduced EE2 uptake rate by 50% relative to 16ppt. Tissue-specific accumulation of EE2 was highest (40-60% of the total) in the liver plus gall bladder across all exposures, and the vast majority of this was in the bile at 2h, regardless of temperature or salinity. The carcass was the next highest accumulator (30-40%), followed by the gut (10-20%) with only small amounts in gill and spleen. Killifish chronically exposed (15 days) to 100ng/L EE2 displayed no difference in EE2 uptake rate or tissue-specific distribution. Drinking rate, measured with radiolabeled polyethylene glycol-4000, was about 25 times greater in 16ppt-acclimated killifish relative to FW-acclimated animals. However, drinking accounted for less than 30% of gut accumulation, and therefore a negligible percentage of whole body EE2 uptake rates. In general, there were strong positive relationships between EE2 uptake rates and MO(2), suggesting similar uptake pathways of these lipophilic molecules across the gills. These data will be useful in developing a predictive model of how key environmental parameter variations (salinity, temperature, dissolved oxygen) affect EE2 uptake in estuarine fish, to determine optimal timing and location of WWTP discharges. Copyright © 2012 Elsevier B.V. All rights reserved.

Organic and inorganic nitrogen uptake by 21 dominant tree species in temperate and tropical forests.

PubMed

Liu, Min; Li, Changcheng; Xu, Xingliang; Wanek, Wolfgang; Jiang, Ning; Wang, Huimin; Yang, Xiaodong

2017-11-01

Evidence shows that many tree species can take up organic nitrogen (N) in the form of free amino acids from soils, but few studies have been conducted to compare organic and inorganic N uptake patterns in temperate and tropical tree species in relation to mycorrhizal status and successional state. We labeled intact tree roots by brief 15N exposures using field hydroponic experiments in a temperate forest and a tropical forest in China. A total of 21 dominant tree species were investigated, 8 in the temperate forest and 13 in the tropical forest. All investigated tree species showed highest uptake rates for NH4+ (ammonium), followed by glycine and NO3- (nitrate). Uptake of NH4+ by temperate trees averaged 12.8 μg N g-1 dry weight (d.w.) root h-1, while those by tropical trees averaged 6.8 μg N g-1 d.w. root h-1. Glycine uptake rates averaged 3.1 μg N g-1 d.w. root h-1 for temperate trees and 2.4 μg N g-1 d.w. root h-1 for tropical trees. NO3- uptake was the lowest (averaging 0.8 μg N g-1 d.w. root h-1 for temperate trees and 1.2 μg N g-1 d.w. root h-1 for tropical trees). Uptake of NH4+ accounted for 76% of the total uptake of all three N forms in the temperate forest and 64% in the tropical forest. Temperate tree species had similar glycine uptake rates as tropical trees, with the contribution being slightly lower (20% in the temperate forest and 23% in the tropical forest). All tree species investigated in the temperate forest were ectomycorrhizal and all species but one in the tropical forest were arbuscular mycorrhizal (AM). Ectomycorrhizal trees showed significantly higher NH4+ and lower NO3- uptake rates than AM trees. Mycorrhizal colonization rates significantly affected uptake rates and contributions of NO3- or NH4+, but depended on forest types. We conclude that tree species in both temperate and tropical forests preferred to take up NH4+, with organic N as the second most important N source. These findings suggest that temperate and tropical forests demonstrate similar N uptake patterns although they differ in physiology of trees and soil biogeochemical processes. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Nucleic acids encoding metal uptake transporters and their uses

DOEpatents

Schroeder, Julian I.; Antosiewicz, Danuta M.; Schachtman, Daniel P.; Clemens, Stephan

1999-01-01

The invention provides LCT1 nucleic acids which encode metal ion uptake transporters. The invention also provides methods of modulating heavy metal and alkali metal uptake in plants. The methods involve producing transgenic plants comprising a recombinant expression cassette containing an LCT1 nucleic acid linked to a plant promoter.

UPTAKE OF BACTERIOPHAGE F2 THROUGH PLANT ROOTS

EPA Science Inventory

A model system was designed to measure viral uptake through the roots of plants and translocation to distal plant parts. For this study, uptake of bacteriophage f2 was measured in corn and bean plants growing in hydroponic solutions. Few phage were detected in plants with uncut r...

Active Uptake of Amino Acids by Leaves of an Epiphytic Vascular Plant, Tillandsia paucifolia (Bromeliaceae).

PubMed

Nyman, L P; Davis, J P; O'dell, S J; Arditti, J; Stephens, G C; Benzing, D H

1987-03-01

Specialized epidermal trichomes on the leaves of the epiphyte, Tillandsia paucifolia (Bromeliaceae) accumulate amino acids from solution. Simultaneous net uptake of 17 amino acids was determined using high performance liquid chromatography. Uptake occurs against concentration gradients at least as high as 10(4).

Nitrogen Uptake and Denitrification in Restored and Unrestored Streams in Urban Maryland, USA

EPA Science Inventory

There is growing interest in rates of nitrate uptake and denitrification in restored streams to better understand the effects of restoration on nitrogen processing. This study quantified nitrate uptake in 2 restored and 2 unrestored streams in Baltimore, Maryland, U.S.A. using n...

Immunization Uptake in Younger Siblings of Children with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Kuwaik, Ghassan Abu; Roberts, Wendy; Zwaigenbaum, Lonnie; Bryson, Susan; Smith, Isabel M.; Szatmari, Peter; Modi, Bonnie M.; Tanel, Nadia; Brian, Jessica

2014-01-01

Background: Parental concerns persist that immunization increases the risk of autism spectrum disorder, resulting in the potential for reduced uptake by parents of younger siblings of children with autism spectrum disorder ("younger sibs"). Objective: To compare immunization uptake by parents for their younger child relative to their…

Plant Growth and Phosphorus Uptake of Three Riparian Grass Species

USDA-ARS?s Scientific Manuscript database

Riparian buffers can significantly reduce sediment-bound phosphorus (P) entering surface water, but control of dissolved P inputs is more challenging. Because plant roots remove P from soil solution, it follows that plant uptake will reduce dissolved P losses. We evaluated P uptake of smooth bromegr...

Aquatic Plant Control Research Program: Chemical Control of Hydrilla in Flowing Water: Herbicide Uptake Characteristics and Concentrations versus Exposure.

DTIC Science & Technology

1988-03-01

and di ecious hydrilla with diquat, endothall, and fluridone , and (c) to examine time-course uptak characteristics of these herbicides by hydrilla...diquat is effective in hydrilla control at a lower rate than is endothall. Uptake of fluridone by excised hydrilla tissue was linear with time when...ambient fluridone levels were 0.1 to 0.5 mg/i. However, a biphasic uptake curve was obtained at the high treatment rate of 1.0 mg/i fluridone . At this

Phytoplankton productivity, respiration, and nutrient uptake and regeneration in the Potomac River, August 1977 - August 1978

USGS Publications Warehouse

Cole, B.E.; Harmon, D.D.

1981-01-01

Rates of phytoplankton productivity, respiration, and nutrient uptake and regeneration are presented. These observations were made on the Potomac River estuary (POTE) during four cruises between August 1977 and August 1978. Four experimental methods were used: carbon uptake using carbon-14, carbon uptake and respiration by a pH method, productivity and respiration by the dissolved oxygen method, and nutrient (NH4+, NO3-, NO2-, PO4=, and SiO2=) uptake and regeneration by colorimetry. The experiments were made at sites representative of conditions in four principal reaches of the tidal Potomac River estuary: near the mouth, seaward of the summer nutrient and phytoplankton maximum, near the region of maximum phytoplankton standing stock , and near the maximum anthropogenic nutrient source. (USGS)

Cellular Uptake of Chloroquine Is Dependent on Binding to Ferriprotoporphyrin IX and Is Independent of NHE Activity in Plasmodium falciparum

PubMed Central

Bray, Patrick G.; Janneh, Omar; Raynes, Kaylene J.; Mungthin, Mathirut; Ginsburg, Hagai; Ward, Stephen A.

1999-01-01

Here we provide definitive evidence that chloroquine (CQ) uptake in Plasmodium falciparum is determined by binding to ferriprotoporphyrin IX (FPIX). Specific proteinase inhibitors that block the degradation of hemoglobin and stop the generation of FPIX also inhibit CQ uptake. Food vacuole enzymes can generate cell-free binding, using human hemoglobin as a substrate. This binding accounts for CQ uptake into intact cells and is subject to identical inhibitor specificity. Inhibition of CQ uptake by amiloride derivatives occurs because of inhibition of CQ–FPIX binding rather than inhibition of the Na+/H+ exchanger (NHE). Inhibition of parasite NHE using a sodium-free medium does not inhibit CQ uptake nor does it alter the ability of amilorides to inhibit uptake. CQ resistance is characterized by a reduced affinity of CQ–FPIX binding that is reversible by verapamil. Diverse compounds that are known to disrupt lysosomal pH can mimic the verapamil effect. These effects are seen in sodium-free medium and are not due to stimulation of the NHE. We propose that these compounds increase CQ accumulation and overcome CQ resistance by increasing the pH of lysosomes and endosomes, thereby causing an increased affinity of binding of CQ to FPIX. PMID:10209030

Kukoamine B promotes TLR4-independent lipopolysaccharide uptake in murine hepatocytes.

PubMed

Yang, Dong; Zheng, Xinchuan; Wang, Ning; Fan, Shijun; Yang, Yongjun; Lu, Yongling; Chen, Qian; Liu, Xin; Zheng, Jiang

2016-09-06

Free bacterial lipopolysaccharide (LPS) is generally removed from the bloodstream through hepatic uptake via TLR4, the LPS pattern recognition receptor, but mechanisms for internalization and clearance of conjugated LPS are less clear. Kukoamine B (KB) is a novel cationic alkaloid that interferes with LPS binding to TLR4. In this study, KB accelerated blood clearance of LPS. KB also enhanced LPS distribution in the hepatic tissues of C57 BL/6 mice, along with LPS uptake in primary hepatocytes and HepG2 cells. By contrast, KB inhibited LPS internalization in Kupffer and RAW 264.7 cells. Loss of TLR4 did not affect LPS uptake into KB-treated hepatocytes. We also detected selective upregulation of the asialoglycoprotein receptor (ASGPR) upon KB treatment, and ASGPR colocalized with KB in cultured hepatocytes. Molecular docking showed that KB bound to ASGPR in a manner similar to GalNAc, a known ASGPR agonist. GalNAc dose-dependently reduced KB internalization, suggesting it competes with KB for ASGPR binding, and ASGPR knockdown also impaired LPS uptake into hepatocytes. Finally, while KB enhanced LPS uptake, it was protective against LPS-induced inflammation and hepatocyte injury. Our study provides a new mechanism for conjugated LPS hepatic uptake induced by the LPS neutralizer KB and mediated by membrane ASGPR binding.

Hepatic FDG uptake is associated with future cardiovascular events in asymptomatic individuals with non-alcoholic fatty liver disease.

PubMed

Moon, Seung Hwan; Hong, Sun-Pyo; Cho, Young Seok; Noh, Tae Soo; Choi, Joon Young; Kim, Byung-Tae; Lee, Kyung-Han

2017-06-01

Hepatic F-18 fluoro-2-deoxyglucose (FDG) uptake is associated with non-alcoholic fatty liver disease (NAFLD) which is an independent risk factor for cardiovascular disease. However, the value of hepatic FDG uptake for predicting future cardiovascular events has not been explored. Study participants were 815 consecutive asymptomatic participants who underwent a health screening program that included FDG positron emission tomography/computed tomography (PET/CT), abdominal ultrasonography, and carotid intima-media thickness (CIMT) measurements (age 51.8 ± 6.0 year; males 93.9%). We measured hepatic FDG uptake and assessed the prognostic significance of this parameter with other cardiovascular risk factors including Framingham risk score and CIMT. Multivariate Cox proportional hazards analyses including all study participants revealed that NAFLD with high-hepatic FDG uptake was the only independent predictor for future cardiovascular events [hazard ratio (HR) 4.23; 95% CI 1.05-17.04; P = .043). Subgroup analysis conducted in the NAFLD group showed that high-hepatic FDG uptake was a significant independent predictor of cardiovascular events (HR 9.29; 95% CI 1.05-81.04; P = .045). This exploratory study suggests that high-hepatic FDG uptake may be a useful prognostic factor for cardiovascular events in individuals with NAFLD.

Harmane: an atypical neurotransmitter?

PubMed

Abu Ghazaleh, Haya; Lalies, Maggie D; Nutt, David J; Hudson, Alan L

2015-03-17

Harmane is an active component of clonidine displacing substance and a candidate endogenous ligand for imidazoline binding sites. The neurochemistry of tritiated harmane was investigated in the present study examining its uptake and release properties in the rat brain central nervous system (CNS) in vitro. At physiological temperature, [(3)H]harmane was shown to be taken up in rat brain cortex. Further investigations demonstrated that treatment with monoamine uptake blockers (citalopram, nomifensine and nisoxetine) did not alter [(3)H]harmane uptake implicating that the route of [(3)H]harmane transport was distinct from the monoamine uptake systems. Furthermore, imidazoline ligands (rilmenidine, efaroxan, 2-BFI and idazoxan) showed no prominent effect on [(3)H]harmane uptake suggesting the lack of involvement of imidazoline binding sites. Subsequent analyses showed that disruption of the Na(+) gradient using ouabain or choline chloride did not block [(3)H]harmane uptake suggesting a Na(+)-independent transport mechanism. Moreover, higher temperatures (50°C) failed to impede [(3)H]harmane uptake implying a non-physiological transporter. The failure of potassium to evoke the release of preloaded [(3)H]harmane from rat brain cortex indicates that the properties of this putative endogenous ligand for imidazoline binding sites do not resemble that of a conventional neurotransmitter. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Social Cognitive Mediators of Sociodemographic Differences in Colorectal Cancer Screening Uptake

PubMed Central

Lo, Siu Hing; Waller, Jo; Vrinten, Charlotte; Kobayashi, Lindsay; von Wagner, Christian

2015-01-01

Background. This study examined if and how sociodemographic differences in colorectal cancer (CRC) screening uptake can be explained by social cognitive factors. Methods. Face-to-face interviews were conducted with individuals aged 60–70 years (n = 1309) living in England as part of a population-based omnibus survey. Results. There were differences in screening uptake by SES, marital status, ethnicity, and age but not by gender. Perceived barriers (stand. b = −0.40, p < 0.001), social norms (stand. b = 0.33, p < 0.001), and screening knowledge (stand. b = 0.17, p < 0.001) had independent associations with uptake. SES differences in uptake were mediated through knowledge, social norms, and perceived barriers. Ethnic differences were mediated through knowledge. Differences in uptake by marital status were primarily mediated through social norms and to a lesser extent through knowledge. Age differences were largely unmediated, except for a small mediated effect via social norms. Conclusions. Sociodemographic differences in CRC screening uptake were largely mediated through social cognitive factors. Impact. Our findings suggest that multifaceted interventions might be needed to reduce socioeconomic inequalities. Ethnic differences might be reduced through improved screening knowledge. Normative interventions could emphasise screening as an activity endorsed by important others outside the immediate family to appeal to a wider audience. PMID:26504782

Ga-68 DOTA-NOC uptake in the pancreas: pathological and physiological patterns.

PubMed

Krausz, Yodphat; Rubinstein, Rina; Appelbaum, Liat; Mishani, Eyal; Orevi, Marina; Fraenkel, Merav; Tshori, Sagi; Glaser, Benjamin; Bocher, Moshe; Salmon, Asher; Chisin, Roland; Gross, David J; Freedman, Nanette

2012-01-01

Gallium-68 (Ga-68) DOTA-1-NaI3-octreotide (DOTA-NOC) positron emission tomography (PET)/computed tomography (CT) is increasingly used for neuroendocrine tumors (NETs), often found primarily in the pancreas. However, physiologic uptake of DOTA-NOC has been described in the uncinate process of the pancreas. We studied DOTA-NOC uptake in this organ. Ninety-six patients underwent 103 DOTA-NOC scans, with pathology-proven pancreatic NET (n = 40) and nonpancreatic NET or biochemical suspicion of NET (n = 63). DOTA-NOC uptake was detected in 35 documented pancreatic tumor sites (SUV: 5.5-165; mean: 25.7 ± 28.8; median: 17.8). Among 63 cases without previous known pathology, uptake was suspicious for tumor in 24 sites (SUV: 4.7-35; mean 16.3 ± 8.0; median: 14.1), and in 38 sites, it was judged as physiological, generally lower relative to adjacent structures (SUV: 2.2-12.6; mean: 6.6 ± 2.2; median: 6.2). In 24 scans with suspected tumor and in 37 of 38 scans with physiological uptake, diagnostic computed tomography or magnetic resonance imaging or endoscopic ultrasonography failed to detect tumor. Pancreatic DOTA-NOC uptake must be interpreted with caution, and further studies are required.

Measurement and modeling of polychlorinated biphenyl bioaccumulation from sediment for the marine polychaete neanthes arenaceodentata and response to sorbent amendment

USGS Publications Warehouse

Janssen, E.M.-L.; Croteau, M.-N.; Luoma, S.N.; Luthy, R.G.

2010-01-01

Bioaccumulation rates of polychlorinated biphenyls (PCBs) for the marine polychaete Neanthes arenaceodentata were characterized, including PCB uptake rates from water and sediment, and the effect of sorbent amendment to the sediment on PCB bioavailability, organism growth, and lipid content. Physiological parameters were incorporated into a biodynamic model to predict contaminant uptake. The results indicate rapid PCB uptake from contaminated sediment and significant organism growth dilution during time-series exposure studies. PCB uptake from the aqueous phase accounted for less than 3% of the total uptake for this deposit-feeder. Proportional increase of gut residence time and assimilation efficiency as a consequence of the organism's growth was assessed by PCB uptake and a reactor theory model of gut architecture. Pulse-chase feeding and multilabeled stable isotope tracing techniques proved high sediment ingestion rates (i.e., 6?10 times of dry body weight per day) indicating that such deposit-feeders are promising biological indicators for sediment risk assessment. Activated carbon amendment reduced PCB uptake by 95% in laboratory experiments with no observed adverse growth effects on the marine polychaete. Biodynamic modeling explained the observed PCB body burdens for N. arenaceodentata, with and without sorbent amendment. ?? 2009 American Chemical Society.

Biogeochemical controls of uranium bioavailability from the dissolved phase in natural freshwaters

USGS Publications Warehouse

Croteau, Marie-Noele; Fuller, Christopher C.; Cain, Daniel J.; Campbell, Kate M.; Aiken, George R.

2016-01-01

To gain insights into the risks associated with uranium (U) mining and processing, we investigated the biogeochemical controls of U bioavailability in the model freshwater speciesLymnaea stagnalis (Gastropoda). Bioavailability of dissolved U(VI) was characterized in controlled laboratory experiments over a range of water hardness, pH, and in the presence of complexing ligands in the form of dissolved natural organic matter (DOM). Results show that dissolved U is bioavailable under all the geochemical conditions tested. Uranium uptake rates follow first order kinetics over a range encompassing most environmental concentrations. Uranium uptake rates in L. stagnalis ultimately demonstrate saturation uptake kinetics when exposure concentrations exceed 100 nM, suggesting uptake via a finite number of carriers or ion channels. The lack of a relationship between U uptake rate constants and Ca uptake rates suggest that U does not exclusively use Ca membrane transporters. In general, U bioavailability decreases with increasing pH, increasing Ca and Mg concentrations, and when DOM is present. Competing ions did not affect U uptake rates. Speciation modeling that includes formation constants for U ternary complexes reveals that the aqueous concentration of dicarbonato U species (UO2(CO3)2–2) best predicts U bioavailability to L. stagnalis, challenging the free-ion activity model postulate.

Functional involvement of the organic cation transporter 2 (rOct2) in the renal uptake of organic cations in rats.

PubMed

Umehara, K-I; Iwatsubo, T; Noguchi, K; Kamimura, H

2008-01-01

This study examined the contribution made by organic cation transporters (hOCT/rOct) to the saturable component of the renal uptake of 1-methyl-4-phenylpyridinium, tetraethylammonium (TEA), cimetidine and metformin into rOct2-expressing HEK293 cells and rat kidney slices. All the test compounds accumulated in the rat kidney slices in a carrier-mediated manner. The Michaelis- Menten constant (K(m)) values for saturable uptake of TEA, cimetidine and metformin into rat kidney slices were relatively comparable with those for the rOct2-expressing HEK293 cells. In addition, the relative uptake activity values of TEA, cimetidine and metformin in rat kidney slices were similar to those in rOct2-expressing HEK293 cells. This suggests that the saturable components involved in the renal uptake of TEA, cimetidine and metformin are mediated mainly by rOct2. The saturable uptake profile of cationic compounds into rat kidney can be evaluated in both cDNA-expressing cells and rat kidney slices, as well as the transporter expression pattern. This approach can also be used to estimate the saturable uptake mechanism of cationic compounds into the human kidney when human kidney slices and hOCT2-expressing cells are used.

Comparison of fluorescence-based methods to determine nanoparticle uptake by phagocytes and non-phagocytic cells in vitro

PubMed Central

Claudia, Meindl; Kristin, Öhlinger; Jennifer, Ober; Eva, Roblegg; Eleonore, Fröhlich

2017-01-01

At many portals of entry the relative uptake by phagocytes and non-phagocytic cells has a prominent effect on availability and biological action of nanoparticles (NPs). Cellular uptake can be determined for fluorescence-labeled NPs. The present study compares three methods (plate reader, flow cytometry and image analysis) in order to investigate the influence of particle size and functionalization and medium content on cellular uptake of fluorescence–labeled polystyrene particles and to study the respective method’s suitability for uptake studies. For comparison between the techniques, ratios of macrophage to alveolar epithelial cell uptakes were used. Presence of serum protein in the exposure solution decreased uptake of carboxyl-functionalized and non-functionalized particles; there was no clear effect for the amine-functionalized particles. The 200 nm non- or carboxyl-functionalized NPs were taken up preferentially by phagocytes while for amine-functionalized particles preference was lowest. The presence of the serum slightly increased the preference for these particles. In conclusion, due to the possibility of calibration, plate reader measurements might present a better option than the other techniques to (semi)quantify differences between phagocytes and non-phagocytic cells for particles with different fluorescence. In order to obtain unbiased data the fluorescent labeling has to fulfill certain requirements. PMID:28065592

Phosphate and ATP uptake by lake bacteria: does taxonomical identity matter?

PubMed Central

Sommaruga, Ruben; Teresa Pérez, María

2016-01-01

Summary Phosphorus often limits bacterial production in freshwater ecosystems. However, little is known on whether different bacteria contribute to inorganic and organic phosphorus uptake proportionally to their relative abundance and production. Here, we followed the temporal dynamics of the main heterotrophic bacterial taxa taking up inorganic phosphate (33P‐Pi) and organic phosphorus (33P‐ATP) in two mountain lakes and compared them to their contribution to bacterial production (3H‐leucine uptake). The short turnover times for Pi and ATP suggested that in both lakes, phosphorus was limiting most of the year. The bulk uptake rates and the fractions of cells labelled positive for Pi and ATP uptake followed a seasonal trend with minima in winter and maxima in summer. Generally, the bacterial taxa examined contributed to Pi and ATP uptake proportionally to their relative abundance, but not always to their contribution to bacterial production. For instance, AcI Actinobacteria were often underrepresented in phosphorus uptake compared with leucine incorporation suggesting they might have high intracellular C:P ratios. Our results emphasize that ATP utilization is widespread among freshwater bacteria and indicate that members within the dominant bacterial taxa (Actinobacteria and Betaproteobacteria) have variable phosphorus requirements, probably due to their different growth potential and variable degrees of homeostasis. PMID:27130525

Fate and Uptake of Pharmaceuticals in Soil–Earthworm Systems

PubMed Central

2014-01-01

Pharmaceuticals present a potential threat to soil organisms, yet our understanding of their fate and uptake in soil systems is limited. This study therefore investigated the fate and uptake of 14C-labeled carbamazepine, diclofenac, fluoxetine, and orlistat in soil–earthworm systems. Sorption coefficients increased in the order of carbamazepine < diclofenac < fluoxetine < orlistat. Dissipation of 14C varied by compound, and for orlistat, there was evidence of formation of nonextractable residues. Uptake of 14C was seen for all compounds. Depuration studies showed complete elimination of 14C for carbamazepine and fluoxetine treatments and partial elimination for orlistat and diclofenac, with greater than 30% of the 14C remaining in the tissue at the end of the experiment. Pore-water-based bioconcentration factors (BCFs), based on uptake and elimination of 14C, increased in the order carbamazepine < diclofenac < fluoxetine and orlistat. Liquid chromatography–tandem mass spectrometry and liquid chromatography–Fourier transform mass spectrometry indicated that the observed uptake in the fluoxetine and carbamazepine treatments was due to the parent compounds but that diclofenac was degraded in the test system so uptake was due to unidentifiable transformation products. Comparison of our data with outputs of quantitative structure−activity relationships for estimating BCFs in worms showed that these models tend to overestimate pharmaceutical BCFs so new models are needed. PMID:24762061

Nanodiamond internalization in cells and the cell uptake mechanism

NASA Astrophysics Data System (ADS)

Perevedentseva, E.; Hong, S.-F.; Huang, K.-J.; Chiang, I.-T.; Lee, C.-Y.; Tseng, Y.-T.; Cheng, C.-L.

2013-08-01

Cell type-dependent penetration of nanodiamond in living cells is one of the important factors for using nanodiamond as cellular markers/labels, for drug delivery as well as for other biomedical applications. In this work, internalization of 100 nm nanodiamonds by A549 lung human adenocarcinoma cell, Beas-2b non-tumorigenic human bronchial epithelial cell, and HFL-1 fibroblast-like human fetal lung cell is studied and compared. The penetration of nanodiamond into the cells was observed using confocal fluorescence imaging and Raman imaging methods. Visualization of the nanodiamond in cells allows comparison of the internalization for diamond nanoparticles in cancer A549 cell, non-cancer HFL-1, and Beas-2b cells. The dose-dependent and time-dependent behavior of nanodiamond uptake is observed in both cancer as well as non-cancer cells. The mechanism of nanodiamond uptake by cancer and non-cancer cells is analyzed by blocking different pathways. The uptake of nanodiamond in both cancer and non-cancer cells was found predominantly via clathrin-dependent endocytosis. In spite of observed similarity in the uptake mechanism for cancer and non-cancer cells, the nanodiamond uptake for cancer cell quantitatively exceeds the uptake for non-cancer cells, for the studied cell lines. The observed difference in internalization of nanodiamond by cancer and non-cancer cells is discussed.

Subunit III-depleted cytochrome c oxidase provides insight into the process of proton uptake by proteins

PubMed Central

Varanasi, Lakshman; Hosler, Jonathan P.

2011-01-01

We review studies of subunit III-depleted cytochrome c oxidase (CcO III (−)) that elucidate the structural basis of steady-state proton uptake from solvent into an internal proton transfer pathway. The removal of subunit III from R. sphaeroides CcO makes proton uptake into the D pathway a rate-determining step, such that measurements of the pH dependence of steady-state O2 consumption can be used to compare the rate and functional pKa of proton uptake by D pathways containing different initial proton acceptors. The removal of subunit III also promotes spontaneous suicide inactivation by CcO, greatly shortening its catalytic lifespan. Because the probability of suicide inactivation is controlled by the rate at which the D pathway delivers protons to the active site, measurements of catalytic lifespan provide a second method to compare the relative efficacy of proton uptake by engineered CcO III (−) forms. These simple experimental systems have been used to explore general questions of proton uptake by proteins, such as the functional value of an initial proton acceptor, whether an initial acceptor must be surface-exposed, which side chains will function as initial proton acceptors and whether multiple acceptors can speed proton uptake. PMID:22023935

Foliar Water Uptake of Tamarix ramosissima from an Atmosphere of High Humidity

PubMed Central

Li, Shuang; Xiao, Hong-lang; Zhao, Liang; Zhou, Mao-Xian; Wang, Fang

2014-01-01

Many species have been found to be capable of foliar water uptake, but little research has focused on this in desert plants. Tamarix ramosissima was investigated to determine whether its leaves can directly absorb water from high humidity atmosphere and, if they can, to understand the magnitude and importance of foliar water uptake. Various techniques were adopted to demonstrate foliar water uptake under submergence or high atmospheric humidity. The mean increase in leaf water content after submergence was 29.38% and 20.93% for mature and tender leaves, respectively. In the chamber experiment, obvious reverse sap flow occurred when relative humidity (RH) was persistently above 90%. Reverse flow was recorded first in twigs, then in branches and stems. For the stem, the percentage of negative sap flow rate accounting for the maximum value of sap flow reached 10.71%, and its amount accounted for 7.54% of diurnal sap flow. Small rainfall can not only compensate water loss of plant by foliar uptake, but also suppress transpiration. Foliar uptake can appear in the daytime under certain rainfall events. High atmospheric humidity is beneficial for enhancing the water status of plants. Foliar uptake should be an important strategy of water acquisition for desert plants. PMID:24982964

Do Chondral Lesions of the Knee Correlate with Bone Tracer Uptake by Using SPECT/CT?

PubMed

Dordevic, Milos; Hirschmann, Michael T; Rechsteiner, Jan; Falkowski, Anna; Testa, Enrique; Hirschmann, Anna

2016-01-01

To evaluate the correlation of bone tracer uptake as determined with single photon emission computed tomography (SPECT)/computed tomography (CT) and the size and severity of chondral lesions detected with magnetic resonance (MR) imaging of the knee. MR imaging and SPECT/CT images of 63 knee joints in 63 patients (mean age ± standard deviation, 49.2 years ± 12.7) with chondral or osteochondral lesions were prospectively collected and retrospectively analyzed after approval by the ethics committee. Chondral lesions were graded on MR images by using a modified Noyes grading scale (grade 0, intact; grade 1, fibrillations; grade 2, <50% defect; grade 3, >50% defect; and grade 4, grade three plus subchondral changes) and measured in two dimensions. Technetium 99m hydroxymethane diphosphonate SPECT/CT bone tracer uptake was volumetrically quantified by using validated software. Maximum values of each subchondral area (patellofemoral or medial and lateral femorotibial) were quantified, and a ratio was calculated in relation to a reference region in the femoral shaft, which represented the bone tracer uptake background activity. Grades and sizes of chondral lesions and bone tracer uptake were correlated by using an independent t test and analysis of variance (P < .05). Bone tracer uptake was low (mean relative uptake, 1.64 ± 0.95) in knees without any present chondral lesion. In knees with grade 3 and 4 chondral lesions, the relative ratio was significantly higher (3.62 ± 2.18, P = .002) than in knees with grade 1 and 2 lesions (2.95 ± 2.07). The larger the diameter of the chondral lesion, the higher the bone tracer uptake. Higher grades of chondral lesions (grades 3 and 4) larger than 4 cm(2) (4.96 ± 2.43) showed a significantly higher bone tracer uptake than smaller lesions (<1 cm(2), 2.72 ± 1.43 [P = .011]; and 1-4 cm(2), 3.28 ± 2.15 [P = .004]). SPECT/CT findings significantly correlate with the degree and size of chondral lesions on MR images. Grade 3 and 4 chondral lesions of the knee, as well as larger lesions, correlate with a high bone tracer uptake. © RSNA, 2015.

Explaining variation in Down's syndrome screening uptake: comparing the Netherlands with England and Denmark using documentary analysis and expert stakeholder interviews.

PubMed

Crombag, Neeltje M T H; Vellinga, Ynke E; Kluijfhout, Sandra A; Bryant, Louise D; Ward, Pat A; Iedema-Kuiper, Rita; Schielen, Peter C J I; Bensing, Jozien M; Visser, Gerard H A; Tabor, Ann; Hirst, Janet

2014-09-25

The offer of prenatal Down's syndrome screening is part of routine antenatal care in most of Europe; however screening uptake varies significantly across countries. Although a decision to accept or reject screening is a personal choice, it is unlikely that the widely differing uptake rates across countries can be explained by variation in individual values alone.The aim of this study was to compare Down's syndrome screening policies and programmes in the Netherlands, where uptake is relatively low (<30%) with England and Denmark where uptake is higher (74 and > 90% respectively), in an attempt to explain the observed variation in national uptake rates. We used a mixed methods approach with an embedded design: a) documentary analysis and b) expert stakeholder analysis. National central statistical offices and legal documents were studied first to gain insight in demographic characteristics, cultural background, organization and structure of healthcare followed by documentary analysis of primary and secondary sources on relevant documents on DSS policies and programme. To enhance interpretation of these findings we performed in-depth interviews with relevant expert stakeholders. There were many similarities in the demographics, healthcare systems, government abortion legislation and Down's syndrome screening policy across the studied countries. However, the additional cost for Down's syndrome screening over and above standard antenatal care in the Netherlands and an emphasis on the 'right not to know' about screening in this country were identified as potential explanations for the 'low' uptake rates of Down's syndrome screening in the Netherlands. The social context and positive framing of the offer at the service delivery level may play a role in the relatively high uptake rates in Denmark. This paper makes an important contribution to understanding how macro-level demographic, social and healthcare delivery factors may have an impact on national uptake rates for Down's syndrome screening. It has suggested a number of policy level and system characteristics that may go some way to explaining the relatively low uptake rates of Down's syndrome screening in the Netherlands when compared to England and Denmark.

The Value of PET/CT in Detecting Bone Marrow Involvement in Patients With Follicular Lymphoma.

PubMed

Perry, Chava; Lerman, Hedva; Joffe, Erel; Sarid, Nadav; Amit, Odelia; Avivi, Irit; Kesler, Mikhail; Ben-Ezra, Jonathan; Even-Sapir, Einat; Herishanu, Yair

2016-03-01

Follicular lymphoma (FL) is the 2nd most common type of lymphoma diagnosed in the Western World. Bone marrow (BM) involvement is an adverse prognostic factor in FL, routinely assessed by an arbitrary biopsy of the iliac crest. This study was aimed to investigate the role of positron emission tomography/computed tomography (PET/CT) in identifying BM involvement by FL. In this retrospective, single-center study we reviewed the records of consecutive patients with FL at diagnosis or relapse who underwent staging/restaging workup visual assessment of BM uptake was categorized as either normal, diffusely increased, or focally increased. Quantitative BM fluorine-18-fluro-deoxyglucose (FDG) uptake was measured using mean standardized uptake value (BM-SUVmean). The diagnosis of BM involvement was based on either BM histological findings or disappearance of increased uptake at end-treatment PET/CT in patients who responded to treatment. Sixty eight cases with FL were included. Sixteen (23.5%) had BM involvement, 13 (19.1%) had a biopsy proven involvement, and 3 (4.4%) had a negative BM biopsy, but increased medullary uptake that normalized post-treatment. BM FDG uptake in these patients was diffuse in 8 (50%) and focal in 8 (50%). Focal increased uptake was indicative of BM involvement; however, diffuse uptake was associated with 17 false positive cases (32.7%). Overall, visual assessment of BM involvement had a negative predictive value (NPV) of 100% and a positive predictive value (PPV) of 48.5%. On a quantitative assessment, BM-SUVmean was significantly higher in patients with BM involvement (SUVmean of 3.7 [1.7-6] vs 1.4 [0.4-2.65], P < 0.001). On receiver operator curve (ROC) analysis, BM-SUVmean > 2.7 had a PPV of 100% for BM involvement (sensitivity of 68%), while BM-SUVmean < 1.7 had an NPV of 100% (specificity of 73%). Visual assessment of PET/CT is appropriate for ruling out BM involvement by FL. Although focal increased uptake indicates marrow involvement, diffuse uptake is nonspecific. SUV measurement improves PET/CT diagnostic accuracy, identifying additional 19% of patients with BM involvement that would have been otherwise missed.

Metabolic responses to BRL37344 and clenbuterol in soleus muscle and C2C12 cells via different atypical pharmacologies and β2-adrenoceptor mechanisms

PubMed Central

Ngala, R A; O'Dowd, J; Wang, S J; Agarwal, A; Stocker, C; Cawthorne, M A; Arch, J R S

2008-01-01

Background and purpose: Picomolar concentrations of the β3-adrenoceptor agonist BRL37344 stimulate 2-deoxyglucose uptake in soleus muscle via undefined receptors. Higher concentrations alter uptake, apparently via β2-adrenoceptors. Effects of BRL37344 and β2-adrenoceptor agonists are compared. Experimental approach: Mouse soleus muscles were incubated with 2-deoxy[1-14C]-glucose, [1-14C]-palmitate or [2-14C]-pyruvate, and BRL37344, β2-adrenoceptor agonists and selective β-adrenoceptor antagonists. Formation of 2-deoxy[1-14C]-glucose-6-phosphate or 14CO2 was measured. 2-Deoxy[1-14C]-glucose uptake and β-adrenoceptor mRNA were measured in C2C12 cells. Key results: 10 pM BRL37344, 10 pM clenbuterol and 100 pM salbutamol stimulated 2-deoxyglucose uptake in soleus muscle by 33–54%. The effect of BRL37344 was prevented by 1 μM atenolol but not by 300 nM CGP20712A or IC3118551, or 1 μM SR59230A; that of clenbuterol was prevented by ICI118551 but not atenolol. 10 nM BRL37344 st4mulated 2-deoxyglucose uptake, whereas 100 nM clenbuterol and salbutamol inhibited uptake. These effects were blocked by ICI118551. Similar results were obtained in C2C12 cells, in which only β2-adrenoceptor mRNA could be detected by RT-PCR. 10 nM BRL37344 and 10 pM clenbuterol stimulated muscle palmitate oxidation. In the presence of palmitate, BRL37344 no longer stimulated 2-deoxyglucose uptake and the effect of clenbuterol was not significant. Conclusions and implications: Stimulation of glucose uptake by 10 pM BRL37344 and clenbuterol involves different atypical pharmacologies. Nanomolar concentrations of BRL37344 and clenbuterol, probably acting via β2-adrenoceptors, have opposite effects on glucose uptake. The agonists preferentially stimulate fat rather than carbohydrate oxidation, but stimulation of endogenous fat oxidation cannot explain why 100 nM clenbuterol inhibited 2-deoxyglucose uptake. PMID:18552870

Tree specific traits vs. stand level characteristics - assessing the source depths of plant water uptake in a mixed forest stand

NASA Astrophysics Data System (ADS)

Seeger, Stefan; Brinkmann, Nadine; Kahmen, Ansgar; Weiler, Markus

2017-04-01

Due to differences in fine root distributions, physiological root characteristics and plant plasticity, the spatial and temporal characteristics of plant water uptake are expected to vary between different tree species. This has implications on the overall water budget of a forest stand as well as on the drought sensitivity of particular trees. A four-year time series of climate data, soil moisture, and stable water isotopes in soil and tree xylem was used to investigate plant water uptake dynamics of four tree species (beech - Fagus sylvatica, spruce - Picea abies, ash - Fraxinus excelsior and maple - Acer pseudoplatanus) in a mixed forest stand. Modeling with a modified version of the soil hydrological model Hydrus-1D allowed us to simulate continuous time series of stable water isotopes in plant water uptake, which were compared to the measured values in tree xylem water and soil water. We found that different estimated species specific fine root distributions and root water uptake parameters lead to very similar simulated water balances and soil water isotope depth profiles for all four species. According to our simulations, differences in evaporative demand (i.e. LAI) had the biggest influence on water uptake and soil water distributions. Comparing the isotopic signatures of simulated root water uptake and measured xylem water, the simulations for beech were most suited to predict the observed signatures of all four species. This indicates that isolated, tree specific parametrized 1-D simulations are not suited to predict actual water uptake of different trees in a mixed stand. Due to overlapping root spaces dominant trees (in our case beeches with an LAI of around 5.5) may influence the soil water storage below accompanying trees (spruces, ashes and maples with LAIs between 1.8 and 3.1) in a degree that their actual water uptake cannot be predicted with 1-D simulations based on their smaller LAI values. Consequently, for a mixed forest stand the interplay of trees with different traits has to be accounted for in order to correctly model plant water uptake of single trees.

UPTAKE OF LIPOPHILIC CADMIUM COMPLEXES BY THREE GREEN ALGAE: INFLUENCE OF HUMIC ACID AND ITS pH DEPENDENCE(1).

PubMed

Boullemant, Amiel; Le Faucheur, Séverine; Fortin, Claude; Campbell, Peter G C

2011-08-01

Cadmium forms neutral, lipophilic CdL2 (0) complexes with diethyldithiocarbamate (L = DDC) and with ethylxanthate (L = XANT). In a synthetic solution and in the absence of natural dissolved organic matter (DOM), for a given total Cd concentration, uptake of these complexes by unicellular algae is much faster than the uptake of the free Cd(2+) cation. The objective of the present study was to determine how this enhanced uptake of the lipophilic CdL2 (0) complexes was affected by the presence of natural DOM (Suwannee River humic acid, SRHA). Experiments were performed with Cd(DDC)2 (0) and Cd(XANT)2 (0) at two pH values (7.0 and 5.5) and with the three chlorophytes [Chlamydomonas reinhardtii P. A. Dang., Pseudokirchneriella subcapitata (Korshikov) Hindák, Chlorella fusca var. vacuolata Shihira et R. W. Krauss]. Short-term uptake (30-40 min) of the CdL2 (0) complexes was followed in the absence and presence of SRHA (6.5 mg C · L(-1) ). Acidification from pH 7.0 to 5.5 decreased CdL2 (0) uptake by the three algae, in the presence or absence of humic acid (HA). The dominant effect of the HA was to decrease Cd uptake, due to its interaction with the CdL2 (0) complexes in solution. However, if uptake of the free CdL2 (0) complexes was compared in the presence and absence of HA, in four of eight cases initial uptake rate constants (ki ) were significantly higher (P < 0.05) in the presence of the HA, suggesting the operation of an interfacial effect of the HA at the algal cell membrane, favoring uptake of CdL2 (0) . Overall, the experimental results suggest that neutral metal complexes will be less bioavailable in natural waters than they are in synthetic laboratory media in the absence of natural DOM. © 2011 Phycological Society of America.

Within-session responses to high-intensity interval training in spinal cord injury.

PubMed

Astorino, Todd Anthony; Thum, Jacob S

2018-02-01

Completion of high-intensity interval training (HIIT) increases maximal oxygen uptake and health status, yet its feasibility in persons with spinal cord injury is unknown. To compare changes in cardiorespiratory and metabolic variables between two interval training regimes and moderate intensity exercise. Nine adults with spinal cord injury (duration = 6.8 ± 6.2 year) initially underwent determination of peak oxygen uptake. During subsequent sessions, they completed moderate intensity exercise, HIIT, or sprint interval training. Oxygen uptake, heart rate, and blood lactate concentration were measured. Oxygen uptake and heart rate increased (p < 0.05) during both interval training sessions and were similar (p > 0.05) to moderate intensity exercise. Peak oxygen uptake and heart rate were higher (p < 0.05) with HIIT (90% peak oxygen uptake and 99% peak heart rate) and sprint interval training (80% peak oxygen uptake and 96% peak heart rate) versus moderate intensity exercise. Despite a higher intensity and peak cardiorespiratory strain, all participants preferred interval training versus moderate exercise. Examining long-term efficacy and feasibility of interval training in this population is merited, considering that exercise intensity is recognized as the most important variable factor of exercise programming to optimize maximal oxygen uptake. Implications for Rehabilitation Spinal cord injury (SCI) reduces locomotion which impairs voluntary physical activity, typically resulting in a reduction in peak oxygen uptake and enhanced chronic disease risk. In various able-bodied populations, completion of high-intensity interval training (HIIT) has been consistently reported to improve cardiorespiratory fitness and other health-related outcomes, although its efficacy in persons with SCI is poorly understood. Data from this study in 9 men and women with SCI show similar changes in oxygen uptake and heart in response to HIIT compared to a prolonged bout of aerobic exercise, although peak values were higher in response to HIIT. Due to the higher peak metabolic strain induced by HIIT as well as universal preference for this modality versus aerobic exercise as reported in this study, further work testing utility of HIIT in this population is merited.

Extracardiac 18F-florbetapir imaging in patients with systemic amyloidosis: more than hearts and minds.

PubMed

Wagner, T; Page, J; Burniston, M; Skillen, A; Ross, J C; Manwani, R; McCool, D; Hawkins, P N; Wechalekar, Ashutosh D

2018-07-01

18 F-Florbetapir has been reported to show cardiac uptake in patients with systemic light-chain amyloidosis (AL). This study systematically assessed uptake of 18 F-florbetapir in patients with proven systemic amyloidosis at sites outside the heart. Seventeen patients with proven cardiac amyloidosis underwent 18 F-florbetapir PET/CT imaging, 15 with AL and 2 with transthyretin amyloidosis (ATTR). Three patients had repeat scans. All patients had protocolized assessment at the UK National Amyloidosis Centre including imaging with 123 I-serum amyloid P component (SAP). 18 F-Florbetapir images were assessed for areas of increased tracer accumulation and time-uptake curves in terms of standardized uptake values (SUV mean ) were produced. All 17 patients showed 18 F-florbetapir uptake at one or more extracardiac sites. Uptake was seen in the spleen in 6 patients (35%; 6 of 9, 67%, with splenic involvement on 123 I-SAP scintigraphy), in the fat in 11 (65%), in the tongue in 8 (47%), in the parotids in 8 (47%), in the masticatory muscles in 7 (41%), in the lungs in 3 (18%), and in the kidney in 2 (12%) on the late half-body images. The 18 F-florbetapir spleen retention index (SRI) was calculated. SRI >0.045 had 100% sensitivity/sensitivity (in relation to 123 I-SAP splenic uptake, the current standard) in detecting splenic amyloid on dynamic imaging and a sensitivity of 66.7% and a specificity of 100% on the late half-body images. Intense lung uptake was seen in three patients, one of whom had lung interstitial infiltration suggestive of amyloid deposition on previous high-resolution CT. Repeat imaging showed a stable appearance in all three patients suggesting no early impact of treatment response. 18 F-Florbetapir PET/CT is a promising tool for the detection of extracardiac sites of amyloid deposition. The combination of uptake in the heart and uptake in the spleen on 18 F-florbetapir PET/CT, a hallmark of AL, suggests that this tracer holds promise as a screening tool for AL.

A systematic review of qualitative findings on factors enabling and deterring uptake of HIV testing in Sub-Saharan Africa

PubMed Central

2013-01-01

Background Despite Sub-Saharan Africa (SSA) being the epicenter of the HIV epidemic, uptake of HIV testing is not optimal. While qualitative studies have been undertaken to investigate factors influencing uptake of HIV testing, systematic reviews to provide a more comprehensive understanding are lacking. Methods Using Noblit and Hare’s meta-ethnography method, we synthesised published qualitative research to understand factors enabling and deterring uptake of HIV testing in SSA. We identified 5,686 citations out of which 56 were selected for full text review and synthesised 42 papers from 13 countries using Malpass’ notion of first-, second-, and third-order constructs. Results The predominant factors enabling uptake of HIV testing are deterioration of physical health and/or death of sexual partner or child. The roll-out of various HIV testing initiatives such as ‘opt-out’ provider-initiated HIV testing and mobile HIV testing has improved uptake of HIV testing by being conveniently available and attenuating fear of HIV-related stigma and financial costs. Other enabling factors are availability of treatment and social network influence and support. Major barriers to uptake of HIV testing comprise perceived low risk of HIV infection, perceived health workers’ inability to maintain confidentiality and fear of HIV-related stigma. While the increasingly wider availability of life-saving treatment in SSA is an incentive to test, the perceived psychological burden of living with HIV inhibits uptake of HIV testing. Other barriers are direct and indirect financial costs of accessing HIV testing, and gender inequality which undermines women’s decision making autonomy about HIV testing. Despite differences across SSA, the findings suggest comparable factors influencing HIV testing. Conclusions Improving uptake of HIV testing requires addressing perception of low risk of HIV infection and perceived inability to live with HIV. There is also a need to continue addressing HIV-related stigma, which is intricately linked to individual economic support. Building confidence in the health system through improving delivery of health care and scaling up HIV testing strategies that attenuate social and economic costs of seeking HIV testing could also contribute towards increasing uptake of HIV testing in SSA. PMID:23497196

Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes.

PubMed

Storey, Stephen M; McIntosh, Avery L; Huang, Huan; Landrock, Kerstin K; Martin, Gregory G; Landrock, Danilo; Payne, H Ross; Atshaves, Barbara P; Kier, Ann B; Schroeder, Friedhelm

2012-04-15

A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in <1 min and initial rate and maximal uptake of HDL free cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2/SCP-x/L-FABP null mice and hepatocytes. Taken together, these results suggest that L-FABP, particularly in the absence of SCP-2, plays a significant role in HDL-mediated cholesterol uptake in cultured primary hepatocytes.

Method of invitation and geographical proximity as predictors of NHS Health Check uptake.

PubMed

Gidlow, Christopher; Ellis, Naomi; Randall, Jason; Cowap, Lisa; Smith, Graham; Iqbal, Zafar; Kumar, Jagdish

2015-06-01

Uptake of NHS Health Checks remains below the national target. Better understanding of predictors of uptake can inform targeting and delivery. We explored invitation method and geographical proximity as predictors of uptake in deprived urban communities. This observational cohort study used data from all 4855 individuals invited for an NHS Health Check (September 2010-February 2014) at five general practices in Stoke-on-Trent, UK. Attendance/non-attendance was the binary outcome variable. Predictor variables included the method of invitation, general practice, demographics, deprivation and distance to Health Check location. Mean attendance (61.6%) was above the city and national average, but varied by practice (47.5-83.3%; P < 0.001). Telephone/verbal invitations were associated with higher uptake than postal invitations (OR = 2.87, 95% CI = 2.26-3.64), yet significant practice-level variation remained. Distance to Health Check was not associated with attendance. Increasing age (OR = 1.04, 95% CI = 1.03-1.04), female gender (OR = 1.48, 95% CI = 1.30-1.68) and living in the least deprived areas (OR = 1.59, 95% CI = 1.23-2.05) were all independent positive predictors of attendance. Using verbal or telephone invitations should be considered to improve Health Check uptake. Other differences in recruitment and delivery that might explain remaining practice-level variation in uptake warrant further exploration. Geographical proximity may not be an important predictor of uptake in urban populations. © The Author 2014. Published by Oxford University Press on behalf of Faculty of Public Health.

Regulation of Iodide Uptake in Placental Primary Cultures

PubMed Central

Burns, R.; O'Herlihy, C.; Smyth, P.P.A.

2013-01-01

Background Maintenance of adequate iodide supply to the developing fetus is dependent not only on maternal dietary iodine intake but also on placental iodide transport. The objective of this study was to examine the effects of different pregnancy-associated hormones on the uptake of radioiodide by the placenta and to determine if iodide transporter expression is affected by hormone incubation. Methods Primary cultures of placental trophoblast cells were established from placentas obtained at term from pre-labor caesarean sections. They were pre-incubated with 17β-estradiol, prolactin, oxytocin, human chorionic gonadotropin (hCG) and progesterone either singly or in combination over 12 h with 125I uptake being measured after 6 h. RNA was isolated from placental trophoblasts and real-time RT-PCR performed using sodium iodide symporter (NIS) and pendrin (PDS) probes. Results Significant dose response increments in 125I uptake by trophoblast cells (p < 0.01) were observed following incubation with hCG (60% increase), oxytocin (45% increase) and prolactin (32% increase). Although progesterone (50-200 ng/ml) and 17β-estradiol (1,000-15,000 pg/ml) alone produced no significant differences in uptake, they facilitated increased uptake when combined with prolactin or oxytocin, with a combination of all four hormones producing the greatest increase (82%). Increased 125I uptake was accompanied by corresponding increments in NIS mRNA (ratio 1.52) compared to untreated control cells. No significantly increased expression levels of PDS were observed. Conclusions Pregnancy-associated hormones, particularly oxytocin and hCG, have a role in promoting placental iodide uptake which may protect the fetus against iodine deficiency. PMID:24783055

Foliar uptake of cesium from the water column by aquatic macrophytes.

PubMed

Pinder, J E; Hinton, T G; Whicker, F W

2006-01-01

The probable occurrence and rate of foliar absorption of stable cesium (133Cs) from the water column by aquatic macrophyte species was analyzed following the addition of 133Cs into a small reservoir near Aiken, South Carolina, USA. An uptake parameter u (10(3)Lkg(-1)d(-1)) and a loss rate parameter k (d(-1)) were estimated for each species using time series of 133Cs concentrations in the water and plant tissues. Foliar uptake, as indicated by rapid increases in plant concentrations following the 133Cs addition, occurred in two floating-leaf species, Brasenia schreberi and Nymphaea odorata, and two submerged species, Myriophyllum spicatum and Utricularia inflata. These species had values of u> or =0.75 x 10(3)Lkg(-1)d(-1). Less evidence for foliar uptake was observed in three emergent species, including Typha latifolia. Ratios of u to k for B. schreberi, M. spicatum, N. odorata and U. inflata can be used to estimate concentration ratios (CR) at equilibrium, and these estimates were generally within a factor of 2 of the CR for 137Cs for these species in the same reservoir. This correspondence suggests that foliar uptake of Cs was the principal absorption mechanism for these species. Assessments of: (1) the prevalence of foliar uptake of potassium, rubidium and Cs isotopes by aquatic macrophytes and (2) the possible importance of foliar uptake of Cs in other lentic systems are made from a review of foliar uptake studies and estimation of comparable u and k values from lake studies involving Cs releases.

Determinants of Uptake of Cervical Cancer Screening Services at a No-cost Reproductive Health Clinic Managed by Nurse-Midwives.

PubMed

Osingada, Charles P; Ninsiima, Gloria; Chalo, Rose N; Muliira, Joshua K; Ngabirano, Tom

2015-01-01

The incidence of cervical cancer (CC) has been rising in sub-Saharan Africa, and health authorities in this region have responded by increasing the availability of cheap or no-cost CC screening services (CCSS), public health education, and others. However, the efforts have not yet resulted into the expected uptake of CCSS. The aim of this study was to examine the determinants of uptake of CCSS at a no-cost reproductive health clinic managed by nurse-midwives. A descriptive design and a structured interview questionnaire were used to collect data from 236 women attending the reproductive health clinic. Logistic regression statistics were used to examine the determinants of uptake of CCSS. The mean age of participants was 28.7 years, and only 29% had received CC screening. The significant determinants of uptake of CCSS were concern about the gender of the healthcare professional (HCP) (odds ratio [OR], 5.03; P = .001), age older than 25 years (OR, 3.09; P = .005), contraceptive use (OR, 0.28; P = .02), encouragement by HCPs (OR, 0.16; P = .00), and perceived quality of CCSS (OR, 0.08; P = .00). Gender of the HCP and encouragement or reminders by the HCP influence uptake of CCSS. Because nurse-midwives have successfully led strategies to promote other integrated reproductive health services, they can also play a key role in enhancing uptake of CCSS in resource-poor settings. Interventions to enhance service quality and deliberate policies requiring HCP to recommend encourage and remind clients may help to enhance uptake of CCSS in resource-poor settings.

Inhibition of Phosphate Uptake in Corn Roots by Aluminum-Fluoride Complexes1

PubMed Central

Façanha, Arnoldo Rocha; Okorokova-Façanha, Anna L.

2002-01-01

F forms stable complexes with Al at conditions found in the soil. Fluoroaluminate complexes (AlFx) have been widely described as effective analogs of inorganic phosphate (Pi) in Pi-binding sites of several proteins. In this work, we explored the possibility that the phytotoxicity of AlFx reflects their activity as Pi analogs. For this purpose, 32P-labeled phosphate uptake by excised roots and plasma membrane H+-ATPase activity were investigated in an Al-tolerant variety of maize (Zea mays L. var. dwarf hybrid), either treated or not with AlFx. In vitro, AlFx competitively inhibited the rate of root phosphate uptake as well as the H+-ATPase activity. Conversely, pretreatment of seedlings with AlFx in vivo promoted no effect on the H+-ATPase activity, whereas a biphasic effect on Pi uptake by roots was observed. Although the initial rate of phosphate uptake by roots was inhibited by AlFx pretreatment, this situation changed over the following minutes as the rate of uptake increased and a pronounced stimulation in subsequent 32Pi uptake was observed. This kinetic behavior suggests a reversible and competitive inhibition of the phosphate transporter by fluoroaluminates. The stimulation of root 32Pi uptake induced by AlFx pretreatment was tentatively interpreted as a phosphate starvation response. This report places AlF3 and AlF4− among Al-phytotoxic species and suggests a mechanism of action where the accumulation of Pi-mimicking fluoroaluminates in the soil may affect the phosphate absorption by plants. The biochemical, physiological, and environmental significance of these findings is discussed. PMID:12177489

Kinetics of 11C-labeled opiates in the brain of rhesus monkeys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartvig, P.; Bergstroem, K.; Lindberg, B.

1984-07-01

The regional uptake in the brain of Rhesus monkeys of i.v. administered 11C-labeled morphine, codeine, heroin and pethidine was studied by means of positron emission tomography. The technique measures the sum of parent drug and radiolabeled metabolites. (For the sake of simplicity the drug derived radioactivity is denoted by the drug name.) Morphine had a limited uptake to discrete areas of the brain. The maximum normalized uptake, with respect to dose per kilogram body weight, was about 0.2, i.e., 20% of the calculated activity if the drug had been evenly distributed throughout the body of the monkey. Maximum radioactivity appearedmore » 30 to 45 min after injection. Morphine left the brain slowly with an estimated half-life of more than 2 hr. An area with a normalized uptake of about 1.0 was detected centrally in the lowest horizontal transsection of the skull. The origin of this area was identified as the pituitary. Codeine, heroin and pethidine were taken up to the brain to a larger extent than morphine, with maximum normalized uptakes of 2.6, 4.6 and 6.3, respectively. Maximum radioactivities of these drugs were achieved earlier and the elimination rates were faster than for morphine. Differences in the uptake of these drugs to the brain, as well as differences in time to maximal normalized uptake and rate of disappearance are considered to reflect differences in the lipophilic character between the drugs. Pethidine had the most rapid and extensive uptake followed by heroin, codeine and morphine in order of decreasing lipophilicity.« less

Methamphetamine Inhibits the Glucose Uptake by Human Neurons and Astrocytes: Stabilization by Acetyl-L-Carnitine

PubMed Central

Szlachetka, Adam M.; Haorah, James

2011-01-01

Methamphetamine (METH), an addictive psycho-stimulant drug exerts euphoric effects on users and abusers. It is also known to cause cognitive impairment and neurotoxicity. Here, we hypothesized that METH exposure impairs the glucose uptake and metabolism in human neurons and astrocytes. Deprivation of glucose is expected to cause neurotoxicity and neuronal degeneration due to depletion of energy. We found that METH exposure inhibited the glucose uptake by neurons and astrocytes, in which neurons were more sensitive to METH than astrocytes in primary culture. Adaptability of these cells to fatty acid oxidation as an alternative source of energy during glucose limitation appeared to regulate this differential sensitivity. Decrease in neuronal glucose uptake by METH was associated with reduction of glucose transporter protein-3 (GLUT3). Surprisingly, METH exposure showed biphasic effects on astrocytic glucose uptake, in which 20 µM increased the uptake while 200 µM inhibited glucose uptake. Dual effects of METH on glucose uptake were paralleled to changes in the expression of astrocytic glucose transporter protein-1 (GLUT1). The adaptive nature of astrocyte to mitochondrial β-oxidation of fatty acid appeared to contribute the survival of astrocytes during METH-induced glucose deprivation. This differential adaptive nature of neurons and astrocytes also governed the differential sensitivity to the toxicity of METH in these brain cells. The effect of acetyl-L-carnitine for enhanced production of ATP from fatty oxidation in glucose-free culture condition validated the adaptive nature of neurons and astrocytes. These findings suggest that deprivation of glucose-derived energy may contribute to neurotoxicity of METH abusers. PMID:21556365

Competition for nitrogen sources between European beech (Fagus sylvatica) and sycamore maple (Acer pseudoplatanus) seedlings.

PubMed

Simon, J; Waldhecker, P; Brüggemann, N; Rennenberg, H

2010-05-01

To investigate the short-term consequences of direct competition between beech and sycamore maple on root N uptake and N composition, mycorrhizal seedlings of both tree species were incubated for 4 days (i.e. beech only, sycamore maple only or both together) in an artificial nutrient solution with low N availability. On the fourth day, N uptake experiments were conducted to study the effects of competition on inorganic and organic N uptake. For this purpose, multiple N sources were applied with a single label. Furthermore, fine roots were sampled and analysed for total amino acids, soluble protein, total nitrogen, nitrate and ammonium content. Our results clearly show that both tree species were able to use inorganic and organic N sources. Uptake of inorganic and organic N by beech roots was negatively affected in the presence of the competing tree species. In contrast, the presence of beech stimulated inorganic N uptake by sycamore maple roots. Both the negative effect of sycamore maple on N uptake of beech and the positive effect of beech on N uptake of sycamore maple led to an increase in root soluble protein in beech, despite an overall decrease in total N concentration. Thus, beech compensated for the negative effects of the tree competitor on N uptake by incorporating less N into structural N components, but otherwise exhibited the same strategy as the competitor, namely, enhancing soluble protein levels in roots when grown under competition. It is speculated that enhanced enzyme activities of so far unknown nature are required in beech as a defence response to inter-specific competition.

Active uptake of substance P carboxy-terminal heptapeptide (5-11) into rat brain and rabbit spinal cord slices.

PubMed

Nakata, Y; Kusaka, Y; Yajima, H; Segawa, T

1981-12-01

We previously reported that nerve terminals and glial cells lack an active uptake system capable of terminating transmitter action of substance P (SP). In the present study, we demonstrated the existence of an active uptake system for SP carboxy-terminal heptapeptide, (5-11)SP. When the slices from either rat brain or rabbit spinal cord were incubated with [3H](5-11)SP, the uptake of (5-11)SP into slices was observed. The uptake system has the properties of an active transport mechanism: it is dependent on temperature and sensitive to hypoosmotic treatment and is inhibited by ouabain and dinitrophenol (DNP). In the brain, (5-11)SP was accumulated by means of a high-affinity and a low-affinity uptake system. The Km and the Vmax values for the high-affinity system were 4.20 x 10(-8) M and 7.59 fmol/10 mg wet weight/min, respectively, whereas these values for the low-affinity system were 1.00 x 10(-6) M and 100 fmol/10 mg wet weight/min, respectively. In the spinal cord, there was only one uptake system, with a Km value of 2.16 x 10(-7) M and Vmax value of 26.2 fmol/10 mg wet weight/min. These results suggest that when SP is released from nerve terminals, it is hydrolysed into (5-11)SP before or after acting as a neurotransmitter, which is in turn accumulated into nerve terminals. Therefore, the uptake system may represent a possible mechanism for the inactivation of SP.

Alkaline stress and iron deficiency regulate iron uptake and riboflavin synthesis gene expression differently in root and leaf tissue: implications for iron deficiency chlorosis

PubMed Central

Hsieh, En-Jung; Waters, Brian M.

2016-01-01

Iron (Fe) is an essential mineral that has low solubility in alkaline soils, where its deficiency results in chlorosis. Whether low Fe supply and alkaline pH stress are equivalent is unclear, as they have not been treated as separate variables in molecular physiological studies. Additionally, molecular responses to these stresses have not been studied in leaf and root tissues simultaneously. We tested how plants with the Strategy I Fe uptake system respond to Fe deficiency at mildly acidic and alkaline pH by measuring root ferric chelate reductase (FCR) activity and expression of selected Fe uptake genes and riboflavin synthesis genes. Alkaline pH increased cucumber (Cucumis sativus L.) root FCR activity at full Fe supply, but alkaline stress abolished FCR response to low Fe supply. Alkaline pH or low Fe supply resulted in increased expression of Fe uptake genes, but riboflavin synthesis genes responded to Fe deficiency but not alkalinity. Iron deficiency increased expression of some common genes in roots and leaves, but alkaline stress blocked up-regulation of these genes in Fe-deficient leaves. In roots of the melon (Cucumis melo L.) fefe mutant, in which Fe uptake responses are blocked upstream of Fe uptake genes, alkaline stress or Fe deficiency up-regulation of certain Fe uptake and riboflavin synthesis genes was inhibited, indicating a central role for the FeFe protein. These results suggest a model implicating shoot-to-root signaling of Fe status to induce Fe uptake gene expression in roots. PMID:27605716

Preliminary Evidence for Adipocytokine Signals in Skeletal Muscle Glucose Uptake.

PubMed

Kudoh, Akihiro; Satoh, Hiroaki; Hirai, Hiroyuki; Watanabe, Tsuyoshi; Shimabukuro, Michio

2018-01-01

The cross talk between the adipose tissue and insulin target tissues is a key mechanism for obesity-associated insulin resistance. However, the precise role of the interaction between the skeletal muscle and adipose tissue for insulin signaling and glucose uptake is questionable. L6 myocytes were co-cultured with or without 3T3-L1 adipocytes (~5 × 10 3 cells/cm 2 ) up to 24 h. Glucose uptake was evaluated by 2-[ 3 H] deoxyglucose uptake assay. Levels of mRNA expression of Glut1 and Glut4 and mitochondrial enzymes were analyzed by quantitative real-time reverse transcription polymerase chain reaction. Levels of Glut1 and Glut4 protein and phosphorylation of Akt (Ser473 and Thr308) were analyzed by immunoblotting. Study 1: co-culture with 3T3-L1 adipocytes increased glucose uptake in dose- and time-dependent manner in L6 myocytes under insulin-untreated conditions. When co-cultured with 3T3-L1 cells, reactive oxygen species production and levels of Glut1 mRNA and protein were increased in L6 cells, while these changes were abrogated and the glucose uptake partially inhibited by antioxidant treatment. Study 2: co-culture with 3T3-L1 adipocytes suppressed insulin-stimulated glucose uptake in L6 myocytes. Insulin-induced Akt phosphorylation at Ser473 decreased, which was proportional to 3T3-L1 density. Antioxidant treatment partially reversed this effect. Interactions between skeletal muscle and adipose tissues are important for glucose uptake under insulin-untreated or -treated condition through oxygen stress mechanism.

Uptake of silver nanoparticles by monocytic THP-1 cells depends on particle size and presence of serum proteins

NASA Astrophysics Data System (ADS)

Kettler, Katja; Giannakou, Christina; de Jong, Wim H.; Hendriks, A. Jan; Krystek, Petra

2016-09-01

Human health risks by silver nanoparticle (AgNP) exposure are likely to increase due to the increasing number of NP-containing products and demonstrated adverse effects in various cell lines. Unfortunately, results from (toxicity) studies are often based on exposure dose and are often measured only at a fixed time point. NP uptake kinetics and the time-dependent internal cellular concentration are often not considered. Macrophages are the first line of defense against invading foreign agents including NPs. How macrophages deal with the particles is essential for potential toxicity of the NPs. However, there is a considerable lack of uptake studies of particles in the nanometer range and macrophage-like cells. Therefore, uptake rates were determined over 24 h for three different AgNPs sizes (20, 50 and 75 nm) in medium with and without fetal calf serum. Non-toxic concentrations of 10 ng Ag/mL for monocytic THP-1 cells, representing realistic exposure concentration for short-term exposures, were chosen. The uptake of Ag was higher in medium without fetal calf serum and showed increasing uptake for decreasing NP sizes, both on NP mass and on number basis. Internal cellular concentrations reached roughly 32/10 %, 25/18 % and 21/15 % of the nominal concentration in the absence of fetal calf serum/with fetal calf serum for 20-, 50- and 75-nm NPs, respectively. Our research shows that uptake kinetics in macrophages differ for various NP sizes. To increase the understanding of the mechanism of NP toxicity in cells, the process of uptake (timing) should be considered.

Energy independent uptake and release of polystyrene nanoparticles in primary mammalian cell cultures.

PubMed

Fiorentino, Ilaria; Gualtieri, Roberto; Barbato, Vincenza; Mollo, Valentina; Braun, Sabrina; Angrisani, Alberto; Turano, Mimmo; Furia, Maria; Netti, Paolo A; Guarnieri, Daniela; Fusco, Sabato; Talevi, Riccardo

2015-01-15

Nanoparticle (NPs) delivery systems in vivo promises to overcome many obstacles associated with the administration of drugs, vaccines, plasmid DNA and RNA materials, making the study of their cellular uptake a central issue in nanomedicine. The uptake of NPs may be influenced by the cell culture stage and the NPs physical-chemical properties. So far, controversial data on NPs uptake have been derived owing to the heterogeneity of NPs and the general use of immortalized cancer cell lines that often behave differently from each other and from primary mammalian cell cultures. Main aims of the present study were to investigate the uptake, endocytosis pathways, intracellular fate and release of well standardized model particles, i.e. fluorescent 44 nm polystyrene NPs (PS-NPs), on two primary mammalian cell cultures, i.e. bovine oviductal epithelial cells (BOEC) and human colon fibroblasts (HCF) by confocal microscopy and spectrofluorimetric analysis. Different drugs and conditions that inhibit specific internalization routes were used to understand the mechanisms that mediate PS-NP uptake. Our data showed that PS-NPs are rapidly internalized by both cell types 1) with similar saturation kinetics; 2) through ATP-independent processes, and 3) quickly released in the culture medium. Our results suggest that PS-NPs are able to rapidly cross the cell membrane through passive translocation during both uptake and release, and emphasize the need to carefully design NPs for drug delivery, to ensure their selective uptake and to optimize their retainment in the targeted cells. Copyright © 2014 Elsevier Inc. All rights reserved.

Deciphering the mechanisms of cellular uptake of engineered nanoparticles by accurate evaluation of internalization using imaging flow cytometry

PubMed Central

2013-01-01

Background The uptake of nanoparticles (NPs) by cells remains to be better characterized in order to understand the mechanisms of potential NP toxicity as well as for a reliable risk assessment. Real NP uptake is still difficult to evaluate because of the adsorption of NPs on the cellular surface. Results Here we used two approaches to distinguish adsorbed fluorescently labeled NPs from the internalized ones. The extracellular fluorescence was either quenched by Trypan Blue or the uptake was analyzed using imaging flow cytometry. We used this novel technique to define the inside of the cell to accurately study the uptake of fluorescently labeled (SiO2) and even non fluorescent but light diffracting NPs (TiO2). Time course, dose-dependence as well as the influence of surface charges on the uptake were shown in the pulmonary epithelial cell line NCI-H292. By setting up an integrative approach combining these flow cytometric analyses with confocal microscopy we deciphered the endocytic pathway involved in SiO2 NP uptake. Functional studies using energy depletion, pharmacological inhibitors, siRNA-clathrin heavy chain induced gene silencing and colocalization of NPs with proteins specific for different endocytic vesicles allowed us to determine macropinocytosis as the internalization pathway for SiO2 NPs in NCI-H292 cells. Conclusion The integrative approach we propose here using the innovative imaging flow cytometry combined with confocal microscopy could be used to identify the physico-chemical characteristics of NPs involved in their uptake in view to redesign safe NPs. PMID:23388071

Non-invasive estimation of 10 B-4-borono-L-phenylalanine-derived boron concentration in tumors by PET using 4-borono-2-18 F-fluoro-phenylalanine.

PubMed

Yoshimoto, Mitsuyoshi; Honda, Natsuki; Kurihara, Hiroaki; Hiroi, Kenta; Nakamura, Satoshi; Ito, Masashi; Shikano, Naoto; Itami, Jun; Fujii, Hirofumi

2018-05-01

In boron neutron capture therapy (BNCT), 10 B-4-borono-L-phenylalanine (BPA) is commonly used as a 10 B carrier. PET using 4-borono-2- 18 F-fluoro-phenylalanine ( 18 F-FBPA PET) has been performed to estimate boron concentration and predict the therapeutic effects of BNCT; however, the association between tumor uptake of 18 F-FBPA and boron concentration in tumors remains unclear. The present study investigated the transport mechanism of 18 F-FBPA and BPA, and evaluated the utility of 18 F-FBPA PET in predicting boron concentration in tumors. The transporter assay revealed that 2-aminobicyclo-(2.2.1)-heptane-2-carboxylic acid, an inhibitor of the L-type amino acid transporter, significantly inhibited 18 F-FBPA and 14 C-4-borono-L-phenylalanine ( 14 C-BPA) uptake in FaDu and LN-229 human cancer cells. 18 F-FBPA uptake strongly correlated with 14 C-BPA uptake in 7 human tumor cell lines (r = .93; P < .01). PET experiments demonstrated that tumor uptake of 18 F-FBPA was independent of the administration method, and uptake of 18 F-FBPA by bolus injection correlated well with BPA uptake by continuous intravenous infusion. The results of this study revealed that evaluating tumor uptake of 18 F-FBPA by PET was useful for estimating 10 B concentration in tumors. © 2018 The Authors.Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Nitrogen uptake by the shoots of smooth cordgrass Spartina alterniflora

USGS Publications Warehouse

Mozdzer, T.J.; Kirwan, M.; McGlathery, K.J.; Zieman, J.C.

2011-01-01

The smooth cordgrass Spartina alterniflora is the foundation species in intertidal salt marshes of the North American Atlantic coast. Depending on its elevation within the marsh, S. alterniflora may be submerged for several hours per day. Previous ecosystem-level studies have demonstrated that S. alterniflora marshes are a net sink for nitrogen (N), and that removal of N from flooding tidal water can provide enough N to support the aboveground biomass. However, studies have not specifically investigated whether S. alterniflora plants assimilate nutrients through their aboveground tissue. We determined in situ foliar and stem N uptake kinetics for 15NH4, 15NO3, and 15N-glycine by artificially flooding plants in a mid-Atlantic salt marsh. To determine the ecological importance of shoot uptake, a model was created to estimate the time of inundation of S. alterniflora in 20 cm height intervals during the growing season. Estimates of inundation time, shoot mass, N uptake rates, and N availability from long-term data sets were used to model seasonal shoot N uptake. Rates of aboveground N uptake rates (leaves + stems) were ranked as follows: NH4 + > glycine > NO3 -. Our model suggests that shoot N uptake may satisfy up to 15% of the growing season N demand in mid-Atlantic salt marshes, with variation depending on plant elevation and water column N availability. However, in eutrophic estuaries, our model indicates the potential of the plant canopy as a nutrient filter, with shoot uptake contributing 66 to 100% of plant N demand. ?? 2011 Inter-Research.

Toward development of an in vitro model of methamphetamine-induced dopamine nerve terminal toxicity.

PubMed

Kim, S; Westphalen, R; Callahan, B; Hatzidimitriou, G; Yuan, J; Ricaurte, G A

2000-05-01

To develop an in vitro model of methamphetamine (METH)-induced dopamine (DA) neurotoxicity, striatal synaptosomes were incubated at 37 degrees C with METH for different periods of time (10-80 min), washed once, then tested for DA transporter function at 37 degrees C. METH produced time- and dose-dependent reductions in the V(max) of DA uptake, without producing any change in K(m). Incubation of synaptosomes with the DA neurotoxins 1-methyl-4-phenyl-pyridinium ion, 6-hydroxydopamine, and amphetamine under similar conditions produced comparable effects. In contrast, incubation with fenfluramine, a serotonin neurotoxin, did not. METH-induced decreases in DA uptake were selective, insofar as striatal glutamate uptake was unaffected. Various DA transporter blockers (cocaine, methylphenidate, and bupropion) afforded complete protection against METH-induced decreases in DA uptake, without producing any effect themselves. METH's effects were also temperature dependent, with greater decreases in DA uptake occurring at higher temperatures. Tests for residual drug revealed small amounts (0.1-0.2 microM) of remaining METH, but kinetic studies indicated that decreases in DA uptake were not likely to be due to METH acting as a competitive inhibitor of DA uptake. Decreases in the V(max) of DA uptake were not accompanied by decreases in B(max) of [(3)H]WIN 35,428 binding, possibly because there is no mechanism for removing damaged DA nerve endings from the in vitro preparation Collectively, these results give good support to the development of a valid in vitro model that may prove helpful for elucidating the mechanisms underlying METH-induced DA neurotoxicity.

Arsenic-phosphorus interactions in the soil-plant-microbe system: Dynamics of uptake, suppression and toxicity to plants.

PubMed

Anawar, Hossain M; Rengel, Zed; Damon, Paul; Tibbett, Mark

2018-02-01

High arsenic (As) concentrations in the soil, water and plant systems can pose a direct health risk to humans and ecosystems. Phosphate (Pi) ions strongly influence As availability in soil, its uptake and toxicity to plants. Better understanding of As(V)-Pi interactions in soils and plants will facilitate a potential remediation strategy for As contaminated soils, reducing As uptake by crop plants and toxicity to human populations via manipulation of soil Pi content. However, the As(V)-Pi interactions in soil-plant systems are complex, leading to contradictory findings among different studies. Therefore, this review investigates the role of soil type, soil properties, minerals, Pi levels in soil and plant, Pi transporters, mycorrhizal association and microbial activities on As-Pi interactions in soils and hydroponics, and uptake by plants, elucidate the key mechanisms, identify key knowledge gaps and recommend new research directions. Although Pi suppresses As uptake by plants in hydroponic systems, in soils it could either increase or decrease As availability and toxicity to plants depending on the soil types, properties and charge characteristics. In soil, As(V) availability is typically increased by the addition of Pi. At the root surface, the Pi transport system has high affinity for Pi over As(V). However, Pi concentration in plant influences the As transport from roots to shoots. Mycorrhizal association may reduce As uptake via a physiological shift to the mycorrhizal uptake pathway, which has a greater affinity for Pi over As(V) than the root epidermal uptake pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

Examining urea flux across the intestine of the spiny dogfish, Squalus acanthias.

PubMed

Gary Anderson, W; McCabe, Chris; Brandt, Catherine; Wood, Chris M

2015-03-01

Recent examination of urea flux in the intestine of the spiny dogfish shark, Squalus acanthias, has shown that feeding significantly enhances urea uptake across the intestine, and this was significantly inhibited following mucosal addition of phloretin. The present study examined potential mechanisms of urea uptake across the dogfish intestine in starved and fed dogfish. Unidirectional flux chambers were used to examine the kinetics of urea uptake, and to determine the influence of sodium, ouabain, competitive urea analogues, and phloretin on urea uptake across the gut of fed dogfish. Intestinal epithelial preparations from starved and fed dogfish were mounted in Ussing chambers to examine the effect of phloretin on bidirectional solute transport across the intestine. In the unidirectional studies, the maximum uptake rate of urea was found to be 35.3±6.9 μmol.cm(-2).h(-1) and Km was found to be 291.8±9.6 mM in fed fish, and there was a mild inhibition of urea uptake following mucosal addition of competitive agonists. Addition of phloretin, Na-free Ringers and ouabain to the mucosal side of intestinal epithelia also led to a significant reduction in urea uptake in fed fish. In the Ussing chamber studies there was a net influx of urea in fed fish and a small insignificant efflux in starved fish. Addition of phloretin blocked urea uptake in fed fish when added to the mucosal side. Furthermore, phloretin had no effect on ion transport across the intestinal epithelia with the exception of the divalent cations, magnesium and calcium. Copyright © 2015 Elsevier Inc. All rights reserved.

Root Water Uptake and Soil Moisture Pattern Dynamics - Capturing Connections, Controls and Causalities

NASA Astrophysics Data System (ADS)

Blume, T.; Heidbuechel, I.; Hassler, S. K.; Simard, S.; Guntner, A.; Stewart, R. D.; Weiler, M.

2015-12-01

We hypothesize that there is a shift in controls on landscape scale soil moisture patterns when plants become active during the growing season. Especially during the summer soil moisture patterns are not only controlled by soils, topography and related abiotic site characteristics but also by root water uptake. Root water uptake influences soil moisture patterns both in the lateral and vertical direction. Plant water uptake from different soil depths is estimated based on diurnal fluctuations in soil moisture content and was investigated with a unique setup of 46 field sites in Luxemburg and 15 field sites in Germany. These sites cover a range of geologies, soils, topographic positions and types of vegetation. Vegetation types include pasture, pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 3-5 soil moisture and soil temperature profiles, matrix potential, piezometers and sapflow sensors as well as standard climate data. At sites with access to a stream, discharge or water level is also recorded. The analysis of soil moisture patterns over time indicates a shift in regime depending on season. Depth profiles of root water uptake show strong differences between different forest stands, with maximum depths ranging between 50 and 200 cm. Temporal dynamics of signal strength within the profile furthermore suggest a locally shifting spatial distribution of root water uptake depending on water availability. We will investigate temporal thresholds (under which conditions spatial patterns of root water uptake become most distinct) as well as landscape controls on soil moisture and root water uptake dynamics.

[Myocardial imaging in acute myocardial infarction using beta-methyl-p-(123I)-iodophenylpentadecanoic acid: comparison with 201Tl imaging and wall motion].

PubMed

Naruse, H; Itano, M; Kondo, T; Kogame, T; Yamamoto, J; Morita, M; Kawamoto, H; Fukutake, N; Ohyanagi, M; Iwasaki, T

1992-01-01

Myocardial imaging using beta-methyl-p-(123I)-iodophenylpentadecanoic acid (BMIPP) was performed in 11 patients with acute myocardial infarction. The left ventricular images were divided into 12 segments, and myocardial imagings with BMIPP were compared with coronary angiography (CAG), thallium-201 myocardial scintigraphy (TL) and wall motion obtained by two-dimensional echocardiography (WM). When the culprit lesion was at the proximal point of the left anterior descending artery (LAD), all segments showed depressed uptake. In 3 cases with single vessel disease of the LAD, inferior wall of the basis showed reduced uptake of BMIPP despite the location of the culprit lesion. In cases with discordant uptake between the two tracers, BMIPP frequently showed more severely depressed uptake than TL in the subacute phase, although the uptake of BMIPP correlated with that of TL (tau = 0.82, p less than 0.001). In such cases, the discordance was related to the improvement in WM from the acute phase to the convalescent phase. BMIPP uptake correlated with WM in the subacute phase (tau = 0.50, p less than 0.001). BMIPP showed more severely depressed uptake while WM showed mild asynergy in most cases in which discordance was found between the BMIPP and WM findings. However, there was no correlation between the change in WM from the acute to subacute phases, or the uptakes of BMIPP and TL alone. We concluded that the myocardial condition can be evaluated in detail in acute myocardial infarction by comparing the findings of BMIPP with those of TL and WM.

Relationship between root water uptake and soil respiration: A modeling perspective

NASA Astrophysics Data System (ADS)

Teodosio, Bertrand; Pauwels, Valentijn R. N.; Loheide, Steven P.; Daly, Edoardo

2017-08-01

Soil moisture affects and is affected by root water uptake and at the same time drives soil CO2 dynamics. Selecting root water uptake formulations in models is important since this affects the estimation of actual transpiration and soil CO2 efflux. This study aims to compare different models combining the Richards equation for soil water flow to equations describing heat transfer and air-phase CO2 production and flow. A root water uptake model (RWC), accounting only for root water compensation by rescaling water uptake rates across the vertical profile, was compared to a model (XWP) estimating water uptake as a function of the difference between soil and root xylem water potential; the latter model can account for both compensation (XWPRWC) and hydraulic redistribution (XWPHR). Models were compared in a scenario with a shallow water table, where the formulation of root water uptake plays an important role in modeling daily patterns and magnitudes of transpiration rates and CO2 efflux. Model simulations for this scenario indicated up to 20% difference in the estimated water that transpired over 50 days and up to 14% difference in carbon emitted from the soil. The models showed reduction of transpiration rates associated with water stress affecting soil CO2 efflux, with magnitudes of soil CO2 efflux being larger for the XWPHR model in wet conditions and for the RWC model as the soil dried down. The study shows the importance of choosing root water uptake models not only for estimating transpiration but also for other processes controlled by soil water content.

Research Paper. Nutrient uptake and mineralization during leaf decay in streams-a model simulation.

Treesearch

J.R. Webster; J.D. Newbold; S.A. Thomas; H.M. Valett; P.J. Mulholland

2009-01-01

We developed a stoichiometrically explicit computer model to examine how heterotrophic uptake of nutrients and microbial mineralization occurring during the decay of leaves in streams may be important in modifying nutrient concentrations. The simulations showed that microbial uptake can substantially decrease stream nutrient concentrations during the initial phases of...

UPTAKE AND ELIMINATION OF IONIZABLE ORGANIC CHEMICALS AT FISH GILLS: PART I. MODEL FORMULATION, PARAMETERIZATION, AND BEHAVIOR

EPA Science Inventory

Effects of pH and alkalinity on uptake and elimination of ionizable organic chemicals at the gills of large rainbow trout were studied. Increased pH reduced uptake rates of weakly-acidic chlorinated phenols and increased that of weakly-basic 3,4-dichlorobenzylamine, indicating gr...

Uptake of organic nitrogen by plants

Treesearch

Torgny Nasholm; Knut Kielland; Ulrika Ganeteg

2009-01-01

Languishing for many years in the shadow of plant inorganic nitrogen (N) nutrition research, studies of organic N uptake have attracted increased attention during the last decade. The capacity of plants to acquire organic N, demonstrated in laboratory and field settings, has thereby been well established. Even so, the ecological significance of organic N uptake for...

Discordant hepatic uptake between Tc-99m sulfur colloid and Tc-99m DISIDA in hypervitaminosis A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vincent, L.M.; McCartney, W.H.; Mauro, M.A.

1984-02-01

Scintigraphic findings in a patient with biopsy-proven hypervitaminosis A included markedly impaired hepatic uptake of Tc-99m sulfur colloid but essentially normal uptake of Tc-99m DISIDA. This case presents a potential cause for image discordance with these two agents.

Uptake in Incidental Focus on Form in Meaning-Focused ESL Lessons

ERIC Educational Resources Information Center

Loewen, Shawn

2004-01-01

Uptake is a term used to describe learners' responses to the provision of feedback after either an erroneous utterance or a query about a linguistic item within the context of meaning-focused language activities. Some researchers argue that uptake may contribute to second language acquisition by facilitating noticing and pushing learners to…