High-performance liquid chromatographic determination of cotinine in urine in isocratic mode

A simple procedure for the determination of cotinine, major metabolite of nicotine in urine, is described. The assay involved a liquid–liquid extraction with dichloromethane in alkaline environment. The extract was dried at ambient temperature under a gentle stream of nitrogen. The residue was dissolved in 300 μl of mobile phase and 30 μl aliquot was injected via an automatic sampler into the liquid chromatograph and eluted with the mobile phase (10–9%, v/v methanol and acetonitrile, respectively in potassium dihydrogenphosphate buffer adjusted to pH 3.4) at a flow rate of 1 ml/min on a C₈ Symmetry cartridge column (5 μm, 150 mm×3.9 mm, Waters) at 25°C. The eluate was detected at 260 nm. Internal standard was 2-phenylimidazole. Sensitive and specific, this technique was performed to test urine of diabetic patients (smokers and non-smokers) admitted in an endocrinology service. Urinary cotinine seems to be a better marker of smoking status than thiocyanates.     

Étude de la décomposition de la matière organique dans le sol au moyen de carbone radioactif

Conclusions Par l'emploi de substrats radioactifs, il a été possible de montrer que le glucose, le ray-grass tel quel, la fraction soluble, les hemicelluloses et la fraction cellulosique du ray-grass ne sont pas, dans les conditions expérimentales appliquées, entièrement transformés en CO₂ dans le sol après une période de deux mois.La décomposition du glucose est plus rapide que celle des hemicelluloses et celle-ci est plus rapide que celle de la fraction cellulosique. Pour le glucose et pour la fraction cellulosique, 11% et 15% respectivement ne se retrouvent pas sous forme de C¹⁴O₂ tandis que pour la fraction soluble, pour les hemicelluloses et pour le ray-grass tel quel, c'est près de 20% qui ne sont pas oxydés en CO₂.La décomposition de chacun de ces substrats radioactifs donne encore lieu à la production de produits organiques radioactifs que l'on trouve dans la fraction des substances solubles, dans la fraction groupant l'- et le -humus et dans l'humine. La radioactivité de cette dernière fraction est du même ordre de grandeur que la somme des deux autres fractions.Travail effectué sous les auspices de l'Institut pour l'Encouragement de la Recherche Scientifique dans l'Industrie et l'Agriculture (I.R.S.I.A.).     

Isolation of protein from humic acid extracted from soil

Summary Chromatography of humic acid in a phenol containing solvent system reveals, in the case of the three types of soil analyzed, the presence of humoprotein containing 11 per cent of nitrogen. Isolation of a humoprotein complex from humic acid, according to the method used by Kirby, followed by paper chromatography allowed the isolation of a protein fraction containing 14.8 per cent nitrogen. This fraction is not dialysable; it has a maximum absorption in ultraviolet light between 260–280 mµ, a small electronegative charge and gives rise to twenty different amino acids. This is the first time that a protein has been separated from humus. Thereby demonstrating that part of the nitrogen contained in humic acid is in the form of protein protected from decomposition.Research supported by the Institut pour l'Encouragement de la Recherche Scientifique dans l'Industrie et l'Agriculture (I.R.S.I.A.).     

Le syndrome de Klinefelter à 20 ans: A propos de 426 observations

Based on a personal series of 426 consecutive observations, the authors look into the different clinical, psychological and biological aspects of Klinefelter' syndrome in subjects aged around twenty. They emphasize the misleading forms and the need to get the karyotype in all patients presenting with any genitalia or pubertal development abnormalities. Testosterone treatment must be given as early as possible around the age of 11–12 years. This therapy is always beneficial in all aspects including the improvement of the psychosocial adjustment.     

Optimization and characterization of an extracellular polysaccharide produced byMoniliella pollinis

Summary A yeast strainMoniliella pollinis produces an extracellular highly viscous gum-like polysaccharide of glucan type in a simple mineral medium. Optimum conditions for its production and properties are described. The viscosity decreased after lyophilization.     

Rate of 14CO2 production from variously labeled forms of [14C]glucose in human breast invasive ductal carcinoma tissues

To establish possible cancerous aggressiveness between the metabolism of variously labeled [14C]glucose in the human breast invasive ductal carcinoma (IDC) tissues, we measured the rates of 14CO2 production from those tissues by using radiorespirometry, expressing the results as initial velocity (V) in nanomoles of 14CO2 min-1 g-1 of fresh tissues. The Vc data were compared with results of the SBR system, which grades up from I to III. Vc,1 values measured with [1-14C]glucose increased from 1.99-2.82 for SBR I to 3.90-4.09 for SBR II, finally reaching 4.83-7.04 for SBR III, thus matching clearly the increase of IDC cancerous aggressiveness. Conversely, data obtained from [3,4-14C]glucose and [6-14C]glucose decreased with increasing cancer stage: i.e., with [3,4-14C]glucose, Vc,3,4 values were 5.79-9.34 for SBR I, 4.45-4.84 for SBR II, and 2.35-1.90 for SBR III; with [6-14C]glucose, the corresponding Vc,6 values were 1.34-1.90, 1.33-1.41, and 0.72-0.79. The Vn,1/Vn,6 ratios were close to unity for normal tissues and for noncancerous tissues surrounding SBRI tumors. For cancerous tissues, however, the Vc,1/Vc,6 ratios were 1.5, 2.9, and 6.1-9.8 in IDC tissues graded as SBR I, II, and III, respectively. The results suggest the possible use of radiorespirometry as a tool to assess IDC aggressiveness.     

La prise en charge du diabète de type 2 : l’HbA1c reste-t-elle le seul objectif ?

HbA1c remains today the main tool for diabetes follow-up. The large scale studies have shown that intensive therapeutic strategies, based on low HbA1c target, were followed by a short-term decrease in microvascular complications, and a short- and long-terms decrease in both micro- and macrovascular complications of diabetes. While a prompt normoglycaemia is strongly encouraged, severe hypoglycaemia must be absolutely avoided. It has been clearly proved that there is a need to control the whole cardiovascular risks, as represented by blood pressure and lipid level in particular, according to the results of the Steno 2 study. The HbA1c target definition should take into account the age, the diabetes duration and the cardiovascular risk factors. Thus, the intensive treatment of type 2 diabetes needs to be quite rapid, not too quick, has to avoid hypoglycaemia, and has to be combined with a strict control of the other cardiovascular risk factors. HbA1c is then a crucial target in type 2 diabetes management, but is not the only one.     

Extraction and study of soil enzymes metabolising tryptophan

Summary The dialysed humic acids obtained from a forest Mull by extraction of a diluted solution of sodium carbonate are enzymatically active. It is found by radiorespirometry that the humic acids act on thel-tryptophan carboxyl C¹⁴, although thed-tryptophan carboxyl suffers no attack. The methylene group and the indole and benzene nuclei are not broken down. Only the carboxyl function is mineralised. Radiochromatography shows that through the action of the humic acids the tryptophan is broken down primarily into indoleacetamide and secondarily into β-indoleacetic acid. From the nature of these compounds it is assumed that the humic acids have an oxygenas effect on thel-tryptophan. The enzymatic activity has its optimum value at 65°C. It is partially inhibited by lyophilisation and by toluene. The pyridoxal phosphate (0.1 μM) has a slight activating influence. The alkalis and mineral acids decompose the enzyme. We can therefore see just how much importance attaches to the humic matter, not only as an energy substrate reserve for the micro-organisms and plants but also as a site for biological activities which are quite distinct from any microbial proliferation and the role of which in plants has still to be studied. It would be of interest to determine the presence of this enzymatic system in other pedologically defined soils and to study it in correlation with their fertility. In addition, there remains the task of detecting the microbial agents in the soil which contribute to the formation of this remarkable enzymatic system.     

Optimization and characterization of an extracellular polysaccharide produced byGlomerella cingulata

Summary A new strain of the fungusGlomerella cingulata has been isolated, which produces an extracellular highly viscous polysaccharide in a simple mineral medium. Optimum conditions for its production and properties are described. The polysaccharide produced was a glucan type. The viscosity remained stable during storage over a period of seven days. Large changes in temperature and pH have no effect on viscosity.