Preservation of amino acids during long term ischemia and subsequent reflow with supplementation of L-arginine, the nitric oxide precursor, in the rat heart.

We investigated whether L-arginine, used in heart preservation to limit endothelial damage, may influence the pool of amino acids during long term ischemia and reflow. Isolated isovolumic rat hearts (n = 23) were submitted to 8 h of hypothermic ischemia after cardioplegic arrest with the Centre de Résonance Magnétique Biologique et Médicale (CRMBM) solution with or without L-arginine (Arg and No Arg groups respectively). Hearts were freeze-clamped after ischemia (n = 11) or submitted to 60 min of reflow (n = 12) and freeze-clamped.

L-arginine during long-term ischemia: effects on cardiac function, energetic metabolism and endothelial damage.

Background: We have evaluated the addition of L-arginine, a precursor of nitric oxide, to a cardioplegic solution (named CRMBM) designed for long-term heart preservation.

Methods: Isolated isovolumic-perfused rat hearts (n = 22) were arrested with the CRMBM solution either with (Arg) or without L-arginine (2 mmol/L) (Arg group, n = 12, vs control group n = 10), submitted to 8 hours of cold storage (4 degrees C) in the solution, and then reperfused for 60 minutes at 37 degrees C. In 11 hearts, we evaluated the quality of cardiac preservation with P-31 magnetic resonance spectroscopy and the measure of function and cellular integrity.

Metabolic and functional effects of low-potassium cardioplegic solutions for long-term heart preservation.

Cardioplegic solutions used to arrest the heart during open heart surgery and cardiac transplantation are based on potassium as a cardioplegic agent in a concentration range of 15-35 mM. However, high to moderate K+ concentrations increase Ca2+ influx and impair endothelial function. We have therefore evaluated the possible advantage of a lower potassium concentration in a new cardioplegic solution (named CRMBM solution) designed for long-term heart preservation.

Optimized cardiac graft preservation: a comparative experimental study using P-31 magnetic resonance spectroscopy and biochemical analyses.

Background: The University of Wisconsin (UW), St. Thomas (ST) and Broussais (B) solutions were compared to the CRMBM solution, that we developed for long term heart preservation.

Methods: Isolated isovolumic rat hearts were arrested with each cardioplegic solution (n = 5) to 8 hearts in each group), submitted to 12 hours of cold storage (4 degrees C) in the same solution and then reperfused for 60 minutes at 37 degrees C.

The influence of temperature on metabolic and cellular protection of the heart during long-term ischemia: a study using P-31 magnetic resonance spectroscopy and biochemical analyses.

We have compared the influence of two different cold temperatures (below 10 degreesC) for cardiac ischemia by measuring a large variety of hemodynamic and metabolic parameters during ischemia and reflow. Isolated isovolumic rat hearts were arrested with a preservation solution which was developed in our laboratory and then submitted to 5 h of cold storage (4 degreesC, group I; and 7.5 degreesC, group II) in the same solution.

Analysis of plasma lipids by NMR spectroscopy: application to modifications induced by malignant tumors.

Lipid extracts of plasma were studied by 31P and 1H NMR spectroscopy at 9.4 T. Signals recorded on lipid mixtures were assigned to different lipid classes using a data base built with two-dimensional 1H COSY spectra of seven standard lipids.

CSF and serum metabolic profile of patients with Huntington's chorea: a study by high resolution proton NMR spectroscopy and HPLC.

We studied both cerebrospinal fluid (CSF) and serum of 11 patients suffering from Huntington's disease (HD) and 12 control subjects by combining high resolution proton NMR spectroscopy and HPLC. NMR spectroscopy analysis of the CSF shows a significant increase (60%) in pyruvate concentration in HD patients. No unexpected molecules were detected.

Catabolism of adenine nucleotides and its relation with intracellular phosphorylated metabolite concentration during ethanol oxidation in perfused rat liver.

Ethanol-induced perturbations in the energy metabolism and in the catabolism of adenine nucleotides were investigated by 31P NMR spectroscopy and HPLC analyses in perfused rat liver. Ethanol oxidation reduced the redox potential of the hepatocyte, leading to an intracellular accumulation of sn-glycerol 3-phosphate. This accumulation, in turn, led to a cytosolic P(i) depletion with stoichiometric relationship close to 1/1 for an initial period of 2 min.

Graphic-aided study of metabolic modifications of plasma in cancer using proton magnetic resonance spectroscopy.

Proton high-resolution MRS of human plasma allows the rapid detection, on the same spectrum, of many compounds originating from different metabolic pathways. In this paper, we illustrate the modifications of the plasma metabolic profiles recorded by proton NMR spectroscopy in different classes of cancers. These modifications can be easily monitored with graphic aids such as 'star plots' which define for each type of cancer a particular pattern describing the most altered metabolic pathways.

[Plasma glycosylated residues demonstrated by proton NMR spectroscopy. Value in the detection of heart graft rejection].

In conjunction with biopsy and Doppler studies, we analysed by high resolution proton NMR spectroscopy the blood plasma of 22 heart transplant recipients. There was a significant variation in the glycosylated residues of proteins with the development of acute cardiac rejection. A more extensive study is underway to assess the sensitivity and specificity of this approach for the early diagnosis of acute cardiac rejection.

High resolution NMR spectroscopy of physiological fluids: from metabolism to physiology.

High resolution NMR spectroscopy of physiological fluids provides quantitative, qualitative and dynamic information on the metabolic status of the interstitial and plasma compartments under a variety of pathophysiological conditions. The simultaneous detection and quantitation by NMR spectroscopy of numerous compounds of the intermediary metabolism offers a new insight in the understanding of the milieu intérieur. NMR spectroscopy of physiological fluids offers a unique way to define and monitor the global metabolic homeostasis in humans.

Quantitation of metabolites in human blood serum by proton magnetic resonance spectroscopy. A comparative study of the use of formate and TSP as concentration standards.

Formate has been evaluated as an alternative standard to quantitate human serum metabolites in 1H NMR spin-echo spectra. The comparison between added formate and 3-(trimethylsilyl) 3,3,3,3-tetradeutero-propionic acid (TSP) shows that, unlike TSP, formate does not interact with serum macromolecules. Transverse and longitudinal proton relaxation times have been measured on several serum metabolites, in the presence of ammonium chloride.

The effects of ethanol concentration on glycero-3-phosphate accumulation in the perfused rat liver. A reassessment of ethanol-induced inhibition of glycolysis using 31P-NMR spectroscopy and HPLC.

The dose-dependent effect of ethanol on the hepatic metabolism of the perfused rat liver has been investigated by (a) 31P-NMR spectroscopy for the follow-up of intracellular phosphorylated metabolites and (b) HPLC for compounds released in the effluents. Perfusion of livers from fed rats with ethanol induced an increase in the level of sn-glycerol 3-phosphate and net accumulations of 3.30 +/- 0.

Early detection of heart transplant rejection using cardiac echography combined with the assay of glycosylated residues in plasma by proton NMR spectroscopy.

Early diagnosis of acute cardiac graft rejection by non-invasive methods is required for medical, organizational, psychological and economic reasons. We have monitored 18 heart recipients over a period of 2.5 years using endomyocardial biopsies (EMB), cardiac Doppler-echography (CDE) and proton NMR spectroscopy assay of plasma glycosylated residues.

[Study of biological fluids by nuclear magnetic resonance spectroscopy].

The use of nuclear magnetic resonance (NMR) spectroscopy in the study of biofluids is rapidly developing and might soon constitute a new major medical application of this technique which benefits from technological and methodological progress such as higher magnetic fields, new probe design, solvent suppression sequences and advanced data processing routines. In this overview, the clinical and pharmacological impact of this new approach is examined, with emphasis on the NMR spectroscopy of plasma, cerebrospinal fluid and urine. Applications to pharmacokinetics and toxicology are illustrated.

Simple cation-exchange high-performance liquid chromatography optimized to the measurement of metabolites in the effluents from perfused rat livers using refractive index and ultraviolet detectors.

A high-performance liquid chromatographic method designed to analyse effluents from perfused organs is described. In the case of rat liver, compounds released by the liver are readily separated and quantitated, using a strong cation exchanger (Aminex HPX 87H), two detectors connected in series (ultraviolet detector at 210 nm and refractive index detector), and by optimizing the concentration of sulphuric acid in the mobile phase. Chromatographic conditions described in the present work enable the quantitation, in a single run, of metabolites derived from the tricarboxylic acid cycle, glycolysis, ketogenesis, adenine nucleotides catabolism and ethanol oxidation.

Variations of plasma sialic acid and N-acetylglucosamine levels in cancer, inflammatory diseases and bone marrow transplantation: a proton NMR spectroscopy study.

Proton NMR spectroscopy allows the detection in plasma of resonances arising from N-acetyl-glucosamine (NAG) and N-acetyl-neuraminic acid (NANA) which have been shown to be borne by acute phase glycoproteins. These resonances can be identified using 2 different protocols of spectrum acquisition detecting different physical states in the global pool of glycoproteins, ie mobile and less mobile moieties of glycosylated chains. In this study we demonstrate that NMR spectroscopy allows a precise monitoring of the variations of glycosylated residues in cancers, inflammatory processes and bone marrow transplantation.

Liposome-mediated delivery of gadolinium-diethylenetriaminopentaacetic acid to hepatic cells: a P-31 NMR study.

Delivery of gadolinium-diethylenetriaminopentaacetic acid (Gd-DTPA) (a magnetic resonance imaging contrast agent) to hepatic cells via liposomes used as carriers was demonstrated and monitored by P-31 NMR spectroscopy at 162 MHz on a perfused rat liver model. The penetration of Gd-DTPA into hepatic cells was reflected by a 41% reduction in the longitudinal relaxation time of the beta phosphorus atom of intrahepatic ATP used as an index of the contrast agent presence. The perfusion of free Gd-DTPA did not affect the relaxation index nor did liposomes devoid of paramagnetic agent.

[Modification of the relative plasma concentrations of methyl and methylene groups in cancer: a study using proton NMR spectroscopy].

Fossel et al. have recently proposed the proton NMR examination of plasmatic lipoproteins--and more precisely the determination of an index obtained from the averaged linewidth of the CH2 and CH3 resonances--as a possible tool for detection of cancer. Many evaluations conducted on an international basis have demonstrated that initial expectations were not met and that the test lacked sensitivity, specificity, and predictive value to be accepted as a screening and diagnostic tool.

Subunit III of ruminant procarboxypeptidase A-S6 complexes and pancreatic proteases E. A new family of pancreatic serine endopeptidases?

Subunit III (BSIII) of the bovine ternary complex of procarboxypeptidase A-S6 (PCPA-S6), a defective serine endopeptidase-like protein, actively synthesized by the pancreas of some ruminant species, is highly homologous to human protease E (HPE). Both proteins possess the same atypical disulfide bridge in position 98-99b. They are structurally related to porcine elastase 1 and human elastase 2 (about 56% identity).