A simple method for quantifying de novo lipogenesis rate and substrate selection in cell cultures by 13 C NMR isotopomer analysis of the crude lipid fraction

2021 ◽  
Author(s):  
João S. Patrício ◽  
Daniela Dias‐Pedroso ◽  
Rui A. Carvalho ◽  
Helena L. A. Viera ◽  
John G. Jones

2001 ◽  
Vol 281 (5) ◽  
pp. E983-E990 ◽  
Author(s):  
Julia J. Krueger ◽  
Xue-Han Ning ◽  
Barisa M. Argo ◽  
Outi Hyyti ◽  
Michael A. Portman

Triiodothyronine (T3) exerts direct action on myocardial oxygen consumption (MV˙o 2), although its immediate effects on substrate metabolism have not been elucidated. The hypothesis, that T3 regulates substrate selection and flux, was tested in isovolumic rat hearts under four conditions: control, T3 (10 nM), epinephrine (Epi), and T3 and Epi (TE). Hearts were perfused with [1,3-13C]acetoacetic acid (AA, 0.17 mM),l-[3-13C]lactic acid (LAC, 1.2 mM), U-13C-labeled long-chain free fatty acids (FFA, 0.35 mM), and unlabeled d-glucose (5.5 mM) for 30 min. Fractional acetyl-CoA contribution to the tricarboxylic acid cycle (Fc) per substrate was determined using 13C NMR and isotopomer analysis. Oxidative fluxes were calculated using Fc, the respiratory quotient, and MV˙o 2. T3increased ( P < 0.05) FcFFA, decreased FcLAC, and increased absolute FFA oxidation from 0.58 ± 0.03 to 0.68 ± 0.03 μmol · min−1 · g dry wt−1( P < 0.05). Epi decreased FcFFA and FcAA, although FFA flux increased from 0.58 ± 0.03 to 0.75 ± 0.09 μmol · min−1 · g dry wt−1. T3 moderated the change in FcFFA induced by Epi. In summary, T3 exerts direct action on substrate pathways and enhances FFA selection and oxidation, although the Epi effect dominates at a high work state.



2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
C. Neves ◽  
T. Rodrigues ◽  
J. Sereno ◽  
C. Simões ◽  
J. Castelhano ◽  
...  

Nonalcoholic fatty liver disease (NAFLD) is caused by excessive liver lipid accumulation, but insulin resistance is specifically associated with impaired lipid saturation, oxidation, and storage (esterification), besides increased de novo lipogenesis. We hypothesized that dietary glycotoxins could impair hepatic lipid metabolism in obesity contributing to lipotoxicity-driven insulin resistance and thus to the onset of nonalcoholic steatohepatitis (NASH). In diet-induced obese rats with methylglyoxal-induced glycation, magnetic resonance spectroscopy, mass spectrometry, and gas chromatography were used to assess liver composition in fatty acyl chains and phospholipids. High-fat diet-induced obesity increased liver lipid fraction and suppressed de novo lipogenesis but did not change fatty acid esterification and saturation or insulin sensitivity. Despite a similar increase in total lipid fraction when supplementing the high-fat diet with dietary glycotoxins, impairment in the suppression of de novo lipogenesis and decreased fatty acid unsaturation and esterification were observed. Moreover, glycotoxins also decreased polyunsaturated cardiolipins and caused oxidative stress, portal inflammation, and insulin resistance in high-fat diet-induced obese rats. Dietary glycated products do not change total lipid levels in the liver of obese rats but dramatically modify the lipidemic profile, leading to oxidative stress, hepatic lipotoxicity, and insulin resistance in obesity and thus contribute to the onset of NASH.



Author(s):  
Dean A. Handley ◽  
Jack T. Alexander ◽  
Shu Chien

In situ preparation of cell cultures for ultrastructural investigations is a convenient method by which fixation, dehydration and embedment are carried out in the culture petri dish. The in situ method offers the advantage of preserving the native orientation of cell-cell interactions, junctional regions and overlapping configurations. In order to section after embedment, the petri dish is usually separated from the polymerized resin by either differential cryo-contraction or solvation in organic fluids. The remaining resin block must be re-embedded before sectioning. Although removal of the petri dish may not disrupt the native cellular geometry, it does sacrifice what is now recognized as an important characteristic of cell growth: cell-substratum molecular interactions. To preserve the topographic cell-substratum relationship, we developed a simple method of tapered rotary beveling to reduce the petri dish thickness to a dimension suitable for direct thin sectioning.



2014 ◽  
Vol 52 (08) ◽  
Author(s):  
T Tolstik ◽  
C Marquardt ◽  
C Matthäus ◽  
C Beleites ◽  
C Krafft ◽  
...  


2020 ◽  
Author(s):  
Neha Bhat ◽  
Anand Narayanan ◽  
Mohsen Fathzadeh ◽  
Mario Kahn ◽  
Leigh Goedeke ◽  
...  


2004 ◽  
Vol 52 (Suppl 1) ◽  
pp. S122.6-S123
Author(s):  
M. Garg ◽  
C. Bell ◽  
L. Rogers ◽  
S. Bassilian ◽  
W. N.P. Lee


Author(s):  
Saygin Abali ◽  
Zehra Yavas Abali ◽  
Kanay Yararbas ◽  
Serap Semiz

Abstract Objectives Familial dysalbuminemic hyperthyroxinemia (FDH) is an autosomal dominant condition caused by heterozygous gain-of-function mutations in the human ALB gene. Case presentation We report, a three-year-old boy with FDH due to p.R242P (or p.R218P without signal peptide) mutation in the ALB gene with a phenotype characterized by extremely high serum total and free thyroxine concentrations. His parents had normal thyroid function tests (TFT), so the mutation detected in this patient is assumed “de novo”. Although the most frequent variant was p.R242H in Caucasians and p.R242P in Japanese, our patient had p.R242P variant. Conclusions Early identification of FDH is fundamental to prevent unnecessary repeats of TFT with different methods. We encourage the ALB gene hot spot sequencing initially and indicate that this molecular diagnosis is a rapid and simple method to diagnose FDH in individuals with euthyroid hyperthyroxinemia.



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