This protocol provides a method for quantitating the intracellular concentrations of endogenous metabolites in cultured cells. The cells are grown in stable isotope-labeled media to near-complete isotopic enrichment and then extracted in organic solvent containing unlabeled internal standards in known concentrations. The ratio of ...

Absolute metabolite concentrations are critical to a quantitative understanding of cellular metabolism, as concentrations impact both the free energies and rates of metabolic reactions. Here we use liquid chromatography-tandem mass spectrometry to quantify more than 100 metabolite ...

Hydrogen 1 (1H) magnetic resonance (MR) spectroscopy enables noninvasive in vivo quantification of metabolite concentrations in the brain. Currently, metabolite concentrations are most often presented as ratios (eg, relative to creatine) rather than as absolute ...

A new high-resolution magic angle spinning nuclear magnetic resonance technique is presented to obtain absolute metabolite concentrations of solutions. The magnetic resonance spectrum of the sample under investigation and an internal reference are acquired simultaneously, ensuring both spectra are obtained under the same experimental ...

Phosphorus-31 NMR spectroscopy using slice selection (DRESS) was used to investigate the absolute concentrations of metabolites in the human liver. Absolute concentrations provide more specific biochemical information compared to spectrum integral ratios. Nine patients with histopathologically ...

We report a new quantitative metabolome profiling technique based on differential (12)C-/(13)C-isotope dansylation labeling of metabolites, fast liquid chromatography (LC) separation and electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) detection. An isotope reagent, (13)C-dansyl chloride, can be readily synthesized. This ...

BackgroundHuman plasma and serum are widely used matrices in clinical and biological studies. However, different collecting procedures and the coagulation cascade influence concentrations of both proteins and metabolites in these matrices. The effects on metabolite concentration profiles have not been fully ...

Metabolite profiling methods are important tools for measurement of metabolite pools in biological systems. While most metabolite profiling methods report relative intensities or depend on a few internal standards representing all metabolites, the ultimate requirement for a quantitative description of the ...

... Title : Absolute Concentration Measurements of Free Radicals in Flames by Absorption Spectroscopy. Descriptive Note : Final rept. ...

Quantitative one-dimensional (1D) ¹H NMR spectroscopy is a useful tool for determining metabolite concentrations because of the direct proportionality of signal intensity to the quantity of analyte. However, severe signal overlap in 1D ¹H NMR spectra of complex metabolite mixtures hinders ...

Image-guided {sup 31}P and 1H magnetic resonance localized spectroscopy was performed on patients with brain tumors, temporal lobe epilepsy, chronic brain stroke, and deep white matter lesions. Absolute molar concentrations of metabolites, peak area ratios, and pH were obtained. The important findings were that {sup 31}P ...

The suppression of the abundant water signal has been traditionally employed to decrease the dynamic range of the NMR signal in proton MRS (1H MRS) in vivo. When using this approach, if the intent is to utilize the water signal as an internal reference for the absolute quantification of metabolites, additional measurements are required for the acquisition ...

Cerebral metabolite disturbances occur among human immunodeficiency virus (HIV)-infected people, and are thought to reflect neuropathology, including proinflammatory processes, and neuronal loss. HIV-associated cortical atrophy continues to occur, though its basis is not well understood, and the relationship of cerebral metabolic disturbance to structural brain abnormalities ...

Concentrations of 3H-8-methoxypsoralen (MOP), its lipid- and water-soluble metabolites, tritiated water, and an insoluble compound have been measured in rat serum, lens, and eye tissue by liquid scintillation, thin-layer chromatography, and other techniques. The radioactivity has been measured in albino and pigmented rats up to 1 week after medication, and ...

Although endogenous steroid hormones, specifically estrogens, androgens, and progestogens, are believed to play critical roles in the etiology of breast, endometrial, ovarian, prostate, and possibly other cancers, research has been limited for many years by the absence of sensitive, accurate methods for measuring the absolute concentrations of steroid ...

Single voxel magnetic resonance spectroscopy with ultrashort echo time was implemented at 16.4 T to enhance the neurochemical profile of the rat brain in vivo. A TE of 1.7 msec was achieved by sequence optimization and by using short-duration asymmetric pulses. Macromolecular signal components were parameterized individually and included in the quantitative analysis, replacing the use of a ...

Different methods exist for an absolute quantification of in vivo proton MR spectra. According to the principle of reciprocity a simple method has been suggested previously, comprising the multiplication of the spectral signals with the unlocalised reference amplitude of the measurement as a correction for the different coil load. Afterwards, the result can be compared to ...

The aim of this study was to characterize the pharmacokinetics and determine the absolute bioavailability and metabolism of DRF 4367, a novel COX-2 inhibitor, in mice. In addition, the in vitro metabolism of DRF 4367 was studied in mouse, rat, dog, monkey and human liver microsomes. Following oral administration, maximum concentrations of DRF 4367 were ...

Metabolomics is a promising tool for discovery of novel biomarkers of chronic disease risk in prospective epidemiologic studies. We investigated the between- and within-person variation of the concentrations of 163 serum metabolites over a period of 4 months to evaluate the metabolite reliability expressed by the intraclass-correlation ...

Metabolomics is a promising tool for discovery of novel biomarkers of chronic disease risk in prospective epidemiologic studies. We investigated the between- and within-person variation of the concentrations of 163 serum metabolites over a period of 4 months to evaluate the metabolite reliability expressed by the intraclass-correlation ...

AimsTo investigate the absolute bioavailability of imidafenacin, a new muscarinic receptor antagonist, a single oral dose of 0.1 mg imidafenacin was compared with an intravenous (i.v.) infusion dose of 0.028 mg of the drug in healthy subjects.MethodsFourteen healthy male subjects, aged 21�45 years, received a single oral dose of 0.1 mg imidafenacin or an i.v. infusion dose ...

This article presents background information related to methodology for estimating brain metabolite concentration from Magnetic Resonance Spectroscopy (MRS) and Magnetic Resonance Spectroscopic Imaging (MRSI) measurements of living human brain tissue. It reviews progress related to this methodology with emphasis placed on progress reported during the past ...

A novel bromoditerpene methyl ketone (1), two new bromoditerpene alcohols featuring a neodolastane (2), and a bromocorodienol skeleton (3), along with 13 previously reported metabolites (4-16) were isolated from the organic extract of Sphaerococcus coronopifolius collected from the rocky coasts of Corfu island in the Ionian Sea. The structures of the new natural products, as ...

The concentrations of mobile high energy phosphorus metabolites and intracellular pH of Langendorff-perfused rabbit heart have been determined under control and reduced flow conditions. Absolute concentration determination was accomplished by Lorentzian lineshape analysis after development of ...

... INTENSITY AND THE CONCENTRATION OF DROPLETS IN MISTS-ACADEMY OF SCIENCES USSR EARTH SCIENCE SECTIONS DOKLADY ...

BackgroundReduced N-acetyl-aspartate (NAA) levels in magnetic resonance spectroscopy (MRS) may visualize axonal damage even in the normal appearing white matter (NAWM). Demyelination and axonal degeneration are a hallmark in multiple sclerosis (MS).ObjectiveTo define the extent of axonal degeneration in the NAWM in the remote from focal lesions in patients with relapsing-remitting (RRMS) and ...