In nutrition studies, para-aminohippuric acid (PAH) is a marker frequently used to measure blood flow in pigs, which is essential for estimating portal-drained viscera (PDV) flux of nutrients. The aim of this study was to evaluate the PAH analytical method by means of qualimetric statistical procedures to estimate the matrix effect and the accuracy and limits of quantitation of the method. Net PDV flux of nutrients was determined in five multi-catheterized pigs using water, plasma or commercial serum as standard matrix. A proportional systematic error due to matrix effect was found for plasma and serum. Mean recovery was 99.4%, and intra- and inter-day precision of the method was 2.4% and 3.8% relative standard deviation, respectively. The limit of quantification was 0.22 mg PAH/l. Use of water for the PAH standard curves underestimated portal blood flow compared with PAH standards prepared with plasma or commercial serum (706, 954 and 927 ml/min; P<0.05, respectively). Consequently, PDV O2 consumption, glucose and amino acids fluxes were underestimated by 33% (P<0.001). In conclusion, our results stress the importance of using plasma from pigs not infused with PAH or alternatively commercial pig serum to prepare PAH standards to determine blood flow in pigs to avoid underestimation of blood flow.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1017/S1751731117001598 | DOI Listing |
Environ Res
January 2025
School of Civil Engineering, Shandong University, Jinan, Shandong, PR China; Laboratory of water-sediment regulation and eco-decontamination, Jinan, Shandong, PR China. Electronic address:
Ammonia assimilation is crucial in microbial nitrogen metabolism, and researching the impact of magnetic field (MF) on heterotrophic ammonia assimilation (HAA) contributes to improving nitrogen utilization and environmental remediation. This study systematically investigated the profound effects of MF stimulation on carbon and ammonia assimilation mechanisms in heterotrophic microorganisms. The dynamic responses of microbial carbon source metabolic efficiency and nitrogen source assimilation rates were quantitatively analyzed by designing a multidimensional stimulation environment of different nutrient levels (C/N 20, 25, 30) and MF intensities (0, 1, 20 mT).
View Article and Find Full Text PDFCurr Opin Biotechnol
January 2025
Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA; Nanovaccine Institute, Iowa State University, Ames, IA, USA. Electronic address:
Metabolic modeling is essential for understanding the mechanistic bases of cellular metabolism in various organisms, from microbes to humans, and the design of fitter microbial strains. Metabolic networks focus on the overall fluxes through biochemical reactions that implicitly rely on several biochemical processes, such as active or diffusive uptake (or export) of nutrients (or metabolites), enzymatic turnover of metabolites, and metal-cofactor enzyme interactions. Despite independent progress in biomolecular simulations, they have yet to be integrated to inform metabolic models.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Biochemistry, University of Zurich, Zurich, Switzerland.
Iron and manganese are essential nutrients whose transport across membranes is catalyzed by members of the SLC11 family. In humans, this protein family contains two paralogs, the ubiquitously expressed DMT1, which is involved in the uptake and distribution of Fe and Mn, and NRAMP1, which participates in the resistance against infections and nutrient recycling. Despite previous studies contributing to our mechanistic understanding of the family, the structures of human SLC11 proteins and their relationship to functional properties have remained elusive.
View Article and Find Full Text PDFMar Pollut Bull
January 2025
State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China.
Investigations of the spatial-temporal variations of nutrients within mangrove coastal zones are essential for assessing the environmental status of an aquatic ecosystems. However, major processes controlling nitrate cycle along the submarine groundwater discharge (SGD) pathway from the mangrove areas to adjacent tidal creek remain underexplored. A time series measurement over a 25 h tidal cycle was conducted in Qinglan Bay tidal creek (Hainan Island, China).
View Article and Find Full Text PDFNat Geosci
November 2024
National Oceanography Centre, Southampton, UK.
The Southern Ocean, a region highly vulnerable to climate change, plays a vital role in regulating global nutrient cycles and atmospheric CO via the biological carbon pump. Diatoms, photosynthetically active plankton with dense opal skeletons, are key to this process as their exoskeletons are thought to enhance the transfer of particulate organic carbon to depth, positioning them as major vectors of carbon storage. Yet conflicting observations obscure the mechanistic link between diatoms, opal and particulate organic carbon fluxes, especially in the twilight zone where greatest flux losses occur.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!