The analysis of peculiar urinary (and other) calculi: an endless source of challenge.

The exact composition of calculi is clinically important, but many specimens are not examined, with resultant loss of important information. We describe the incidence and nature of false stones, peculiar calculi and crystals growing on surprising materials. We studied 3100 calculi (97% urinary, 2% digestive and 1% others). Fourier transform infrared spectroscopy was used to identify calculi by detailed comparison with libraries of reference spectra. We also used UV-visible spectroscopy, nuclear magnetic resonance and gas chromatography-mass spectrometry for specific situations. Among 3100 calculi, 154 (5%) had an unusual composition; 101 specimens (3.3%) were false calculi or artifacts, 31 (1%) contained drugs or metabolites and 22 (0.7%) corresponded to crystallizations around other materials. The findings contribute to immediate patient management and to advances in scientific and medical knowledge. We conclude that the analysis of all calculi must be carried out, to determine their composition, and an efficient strategy must be used.

Structural analysis of 21-hydroxypregn-4-ene-3,20-dione (deoxycorticosterone) derivative compounds. Part II: Proton NMR spectra.

Complete analysis of the proton nuclear magnetic resonance spectrum of desoxycorticosterone (DOC) has been made using selective double irradiation, two-dimensional experiments, relaxation rate, and nuclear Overhauser effect measurements in order to specify the structure and conformation of products encountered during the preparation of the specific antigen DOC-bovine serum albumin (BSA). It has been shown that DOC has the normal P conformation with ring A half-chair, and ring B chair. This confirms results previously obtained by circular dichroism measurements.

Structural analysis of 21-hydroxypregn-4-ene-3,20-dione (deoxycorticosterone) derivative compounds. Part I: Synthesis and circular dichroism identification.

Deoxycorticosterone (DOC) derivative compounds (DOC, DOC 21-acetate, and 7-mercaptopropionic DOC) have been prepared and purified by high pressure liquid chromatography. Synthesis products have been identified, and three chromophores have been displayed by their n----II and II----II dichroic transitions. A normal half-chair conformation is favored in ring A.

GC/MS detection of paraffins in a case of lipoid pneumonia following occupational exposure to oil spray.

A case of lipoid pneumonia following occupational exposure to oil spray is described. Biological fluids (broncho-alveolar lavage and pleural fluid) are analyzed to determine if the compounds found in the industrial oils are present. The samples are purified using high-performance thin-layer chromatography, and after extraction, the compounds were submitted to infrared spectroscopy. Direct hexane extraction of biological fluids is also performed, followed by gas chromatography/mass spectrometry (GC/MS).

Determination of plasma testosterone by mass fragmentography using [3,4-13C]testosterone as an internal standard.

The combination of glass capillary gas chromatography--mass spectrometry is especially suitable for the recognition of compounds. The use of [3,4-13C]testosterone as internal standard, mass fragmentography and isotope ratio measurement have been applied to the quantitative determination of testosterone in plasma. This paper describes the method, using tert.-butyldimethylsilylmethoxime and di-heptafluorobutyrate derivatives. The calibration graph in isotopic dilution is examined. The results obtained are compared with the results obtained by radioimmunoassay. The sensitivity of the method is judged from the lower limit of detection: 4.5 pg. The precision, and inter- and intra-assay are calculated.

[Comparative study of urine immunoelectrophoresis and 4 indexes of glomerular selectivity in chronic glomerulopathies]. / Etude comparative de l'immunoélectrophorèse urinaire et de quatre index de sélectivité glomérulaire au cours des glomérulopathies chroniques.

Glomerular selectivity has been evaluated in a group of 89 patients, using renal clearances of orosomucoid (Cl O), transferrin (cl T) and immunoglobulin G (Cl IgG). In all cases, protein excretion was found above 0,30 g/24 h and urinary immunoelectrophoresis (IEP) showed a glomerular pattern. Clearance ratios Cl IgG/Cl T and Cl T/Cl O as well as Joachim's and Sabot's indexes were correlated to IEP patterns, protein daily excretion, creatinin clearance and pathological findings. The ratio Cl T/Cl O and Joachim's and Sabot's indexes correlated significantly with IEP patterns while Cameron's ratio (Cl IgG/Cl T) did not. Criteria other than Cameron and Joachim's indexes were found to be related to protein excretion; all indexes, Cameron's excluded, were influenced by renal functional status. Progress may be expected from the simultaneous serum and urine determinations of 5 proteins in the range 40 000-1 000 000 molecular weight with more accurate techniques such as laser nephelometry.

Determination of debrisoquine and metabolites in human urine by gas chromatography-mass spectrometry.

A gas chromatographic-mass spectrometric analysis has been developed for the determination of debrisoquine and its metabolites in the urine of healthy individuals (controls) and patients with chronic renal failure. The sensitive and specific assay comprises selected-ion monitoring of the drug and the metabolites 4-hydroxydebrisoquine and 8-hydroxydebrisoquine using guanoxan as the internal standard. The limit of detection is ca. 0.2 microgram/ml. The clinical study shows that the healthy individuals and patients with chronic renal failure can be divided in two groups of extensive metabolizers and poor metabolizers, respectively. The extensive metabolizers excreted large amounts of 4-hydroxydebrisoquine and minor amounts of 8-hydroxydebrisoquine. The poor metabolizers excreted small amounts of 4-hydroxy metabolite, and no 8-hydroxydebrisoquine was detected in the urine.