Individual variations of the seven carbohydrate components of human erythrocyte membrane during aging in vivo

The contents of fucose, mannose, galactose, glucose, 2-acetamido-2-deoxy-d-glucose and -d-galactose, and sialic acid, when the results were expressed as nmol per mg of membrane dry-weights, were found to be significantly lower in the membranes of old erythrocytes than in the membranes of young ones. No significant difference was found between young and old membranes when the compositions were expressed as residues per one hundred carbohydrate residues, suggesting that a homogeneous decrease of the carbohydrate moieties may occur during aging in vivo.     

Biochemical and physiological properties of an extracellular protease produced by Bacillus megaterium

A protease, excreted by a sporogeneous strain of B. megaterium, growing exponentially in a minimum glucose ammonium medium, was isolated. It is a neutral endopeptidase, stabilized by Ca⁺⁺, inhibited by o-phenanthroline, but not by di-isopropylfluorophosphate. The specificity, studied on insulin B-chain, glucagon, cytochrome c, and dipeptides substrates, indicated the need for a dipeptide backbone with both substituted amino and carboxyl groups. A requirement was observed for a nonpolar lateral chain in the amino acid whose amino group was involved in the peptide bond (Leu, Phe, Ala, He, Val). Rates of hydrolysis varied also with the amino acid whose carboxyl group was involved (e.g., His > Ser > Ala > Gly). In complex medium, supplemented with Yeast Extract, the biosynthesis of the protease was repressed during growth, but the same enzyme was excreted during sporulation. The repression was apparently of the same nature as that controlling sporulation during and after growth (e.g., repression by a mixture of amino acids or high concentration of glucose). An asporogeneous mutant showed a normal product ion of protease under all conditions, and a low intracellular protease turnover after growth. A mutant unable to produce protease showed a normal sporulation and a high protein turnover. This protease, here termed megapeptidase, seems to be a typical growth enzyme, not related to either the sporulation process or to the protein turnover after growth.     

Evaluation by electrocorticogram of the protective action of piridoxilate against cerebral hypoxia in rats]

Piridoxilate, at the concentration of 120 mg/kg i.p. in rats, enhanced resistance of these animals to hypoxia (N2 : O2 3,2 %). The electrocorticogram (ECOG) is used to indicate the effectiveness of the drug in lowering the time of electrographic silence, on control (n=19) and pretreated rats (n=12). The ECOG was recorded also during the recovery period under pure oxygen. In pretreated rats, the ECOG records became flat in approximately 551 sec (versus 269 sec on the control group). The latent period of successive steps of cerebral anoxia were delayed in pretreated rats exposed to hypoxia. During the recovery period, piridoxilate seems to enhance the restoration of normal ECOG, as a function of the duration of hypoxia.     

New substance P receptor antagonists. Conception, synthesis and biological evaluation of spirolactam derivatives and their tripeptide Cbz-Pro-Leu-Trp-OBzl(CF3)2 and lactam pseudopeptide derivatives

New chemical entities were designed from the C-terminal sequence of GR71251, an NK₁ pseudopeptide antagonist. Three new NK₁ antagonists were identified with high affinity and selectivity for NK₁ receptors.     

Alterations induced by large doses of furosemide in chronic renal insufficiency.

Eleven patients with different degrees of renal failure with creatinine clearances between 7 and 32 ml/min have been studied. After a standard water overload and control periods of clearances, furosemide 1 g was given/i.v. There followed significant increase of renal plasma flow and glomerular filtration rate. In one case the increase was maintained during a follow up period of 3 hours. A significant increase was evident in phosphate, uric acid, sodium, potassium, and calcium clearances, as well as an increase in the sodium delivery to the distal nephron and a decrease in tubular reabsorption of phosphate. All this may be interpreted as the result of renal vasodilation induced by furosemide and its effect upon the proximal tubule and on Henle's loop.     

Maintenance of MLOs (Mycoplasma-like Organisms) on Populus alba Micropropagation

Populus alba plantlet micropropagation has been used for maintaining MLOs more than three years in samples collected from infected trees in Paris. Symptoms were observed on plantlets obtained from subcultures of the apical, middle and basal parts of the stems, and from the roots. Fluorescent microscopy failed to detect MLOs in the apical part of the plantlets and showed that they increased near the roots. Electron microscopy confirmed their presence. Some root sieve tubes were completely packed with MLOs. The sensitivity of the two methods used, subculturing and microscopy, for detection of MLOs is discussed. The symptoms remained for one year in plants regenerated from diseased plantlets and grown in the greenhouse. Then they started to disappear.