M. Eugene

Proton Nuclear Magnetic Resonance Spectroscopy of Urine and Plasma in Renal Transplantation Follow-Up

Urine and plasma samples from 39 patients who underwent renal transplantation were analyzed by proton nuclear magnetic resonance (NMR) spectroscopy. The most relevant resonances for evaluating renal function after transplantation were those arising from citrate, trimethylamine-N-oxide (TMAO), alanine, and lactate when compared to creatinine. A resonance at 3.7 ppm was related to cyclosporine toxicity when associated with elevated levels of TMAO. The respective variations in these metabolites in urine could contribute to prognosis and diagnosis of renal function impairment related to cyclosporine toxicity or overdosage, or to rejection. Thus, NMR spectroscopy should improve the follow-up and management of renal transplantation patients.

Evaluation of postnatal renal function in fetuses with bilateral obstructive uropathies by proton nuclear magnetic resonance spectroscopy

OBJECTIVES To precisely evaluate fetal renal function in cases of bilateral fetal urinary tract obstruction, we analyzed fetal urine metabolites by nuclear magnetic resonance spectroscopy. STUDY DESIGN Fifty-six specimens of fetal urine samples in utero were retrospectively analyzed by proton nuclear magnetic resonance. Group 1 (n = 21) consisted of survivors for > or = 1 year with normal serum creatinine (< 50 mumol/L), for group 2 (n = 17) of survivors with abnormal serum creatinine (> 50 mumol/L), and group 3 (n = 18) of those with bilateral histologic dysplasia associated with fetal (termination of pregnancy) or neonatal death. RESULTS A specific nuclear magnetic resonance profile was obtained for each of the three groups of renal function. A two-dimensional representation of alanine-valine and valine-threonine concentrations allows clear differentiation between the three degrees of renal function, with a sensitivity and specificity of 88% and 86%, respectively. CONCLUSIONS In fetal bilateral urinary tract obstruction a fetal urine nuclear magnetic resonance profile allows an accurate identification of renal function at birth.

Cell and membrane lipid analysis by proton magnetic resonance spectroscopy in five breast cancer cell lines

The lipid composition of five human breast cancer cell lines (MCF-7, T47D, ZR-75-1, SKBR3 and MDA-MB231) was assessed by proton magnetic resonance spectroscopy (MRS) in whole cells and membrane-enriched fractions. The proportions of the three main lipid resonances in 1D spectra were different for each cell line. These resonances included mobile methyl and methylene functions from fatty acids of triglycerides and phospholipids and N-trimethyl from choline of phospholipids. T47D and ZR-75-1 cells presented a high methylene/methyl ratio (6.02 +/- 0.35 and 6.28 +/- 0.90). This ratio was significantly lower for SKBR3, MCF-7 and MDA-MB231 cells (2.76 +/- 0.22, 2.27 +/- 0.57 and 1.39 +/- 0.39). The N-trimethyl/methyl ratio was high for MDA-MB231 and SKBR3 cells (1.38 +/- 0.54 and 0.86 +/- 0.32), but lower for MCF-7, T47D and ZR-75-1 cells (0.49 +/- 0.11, 0.16 +/- 0.07 and 0.07 +/- 0.03). 2D COSY spectra confirmed these different proportions in mobile lipids. From 1D spectra obtained on membrane preparations, T47D and ZR-75-1 were the only cell lines to retain a signal from mobile methylene functions. These differences might be related to the heterogeneity found for several parameters of these cells (tumorigenicity, growth rate, hormone receptors); an extended number of cases from fresh samples might enable clinical correlations.

pH regulation during ischaemia-reperfusion of isolated rat hearts, and metabolic effects of 2,3-butanedione monoxime

We investigated changes in pHi during ischaemia-reperfusion of isolated rat hearts using phosphorus nuclear magnetic resonance spectroscopy (31P NMR). Hearts were separated into three groups according to the perfusion buffer: bicarbonate-buffered Krebs solution, HEPES-buffered Krebs solution, or bicarbonate-buffered Krebs solution plus 10(-6) M 5-(N-ethyl-N-isopropyl) amiloride (EIPA). In HEPES buffer and in bicarbonate buffer plus EIPA, pH at the end of 30 min of ischaemia and pH oscillations observed during early reperfusion were lower than in bicarbonate buffer. Thus, the presence of two pH regulation mechanisms (Na(+)-H+ antiport and Na(+)-HCO3- symport) was confirmed in the isolated rat heart, while in HEPES buffer, pH was regulated by Na(+)-H+ antiport, and in bicarbonate buffer plus EIPA, by Na(+)-HCO3- symport. When cardiac contraction was inhibited by 10 mM 2, 3-butanedione 2-monoxime (BDM), we observed, in all cases, a less pronounced decrease in pHi at the end of ischaemia, and in pHi oscillations at the onset of reperfusion. These effects were similar to those observed with 150 x 10(-8) M verapamil and might thus be related to a decrease in intracellular calcium. However, with BDM, a greater reduction in the pH recovery rate was observed only in HEPES buffer, suggesting a possible phosphatase-like effect affecting the Na(+)-H+ exchange. Whatever the buffer used, the protective effect of BDM was reflected by an increase in the rate pressure product, which was not observed with verapamil.

Proton magnetic resonance spectroscopy of human amniotic fluids sampled at 17–18 weeks of pregnancy in cases of decreased digestive enzyme activities and detected cystic fibrosis

Low digestive enzyme activities in human amniotic fluid can be observed in normal and disease-affected pregnancies: cystic fibrosis, trisomy 21, intestinal atresia. Amniotic fluids were analyzed by proton nuclear magnetic resonance (NMR) spectroscopy in order to specify prenatally the etiology of low digestive enzyme activities observed at 17-18 weeks of amenorrhea. A total of 114 amniotic fluid samples were collected at 17-18 weeks of amenorrhea. Karyotyping and assays of digestive enzyme activities were performed in all cases. Samples were divided into six groups according to enzyme activities and pathology. Proton spectra were retrospectively recorded. Many compounds, such as amino acids and carboxylic acids, were detected by NMR. The same resonance intensities (normalized to creatinine) were observed in the six groups. Nevertheless, an unidentified resonance at 1.05 ppm was detected in seven out of 13 cases of cystic fibrosis affected fetuses. The NMR spectra demonstrated the stability of the amniotic fluid composition at 17-18 weeks of amenorrhea, even when the fetus was affected by a disease such as trisomy 21 or intestinal atresia. The resonance associated with most cases of cystic fibrosis should be further investigated.

Beneficial effect on rat kidney preservation of the antiischemic agent trimetazidine during cold storage and reperfusion: Assessment by 31P nuclear magnetic resonance spectroscopy

Abstract IN RENAL transplantation, delayed graft function remains a major problem and increases the posttransplant morbidity and hospital costs. Trimetazidine (TMZ), an antiischemic drug, was introduced several years ago and used as an antianginal agent whose main effect is to be devoid of hemodynamic effects. TMZ is a cytoprotective drug that counteracts the metabolic disorders occurring at the level of ischemic cells. Several experimental results have suggested direct actions of the drug on mitochondrial function, intracellular acidosis, and calcium intracellular accumulation. 1,2 The aim of this study was to assess beneficial effect of TMZ during cold storage (CS) with Euro-Collins solution (EC) and normothermic reperfusion on energetic status of the kidneys.

Proton NMR analysis of fecal lipids in gastroenterological patients

Our findings do not support the results of other authors who have found significant differences between CAH and chronic persistent hepatitis (1,7,8) and, accordingly, in our series PIIIP was not found to be clinically useful to predict a diagnosis of CAH whatever the cut-off used. An association between serum PIIIP levels and histologic activity has been reported (5), although other authors did not find such a relationship (6). However, interpretation of histological findings can be hindered because biopsies are subject to sampling errors. We have observed a correlation between PIIIP and aminotransferases in patients with CAH but not in patients with MHD. This fact suggests that cytolytic activity could play a role in the increase of PIIIP in the former patients who have more aggressive liver disease with higher degrees of inflammation and necrosis than the latter. However, a definitive causal relation cannot be established from our findings and additional studies are necessary to elucidate thi§ aspect. We conclude that serum PIIIP concentration has a limited value in the evaluation of patients with CAH and MHD, and its usefulness to differentiate between these two groups of patients is poor. Cytolysis could play a role in the increase in PIIIP in CAH patients.

High-energy phosphate and ventricular function in rat hearts during 12-hour continuous microperfusion at 4°C: Effect of oxygenation

Abstract THE AIM of the present investigation was to determine the effects on isolated rat hearts of microperfusion of a cardioplegic solution 1,2 containing 2,3-butanedione monoxime (BDM) and polyethylene glycol 20,000 daltons (PEG), gassed with different gas mixtures during preservation, and to compare it with the effects of simple cold storage (SCS).