11-Trans leukotriene C: A naturally occurring slow reacting substance

A slow reacting substance, produced by murine mastocytoma cells, has been shown to have the structure 5(S)-hydroxy-6(R)-$\text{S}$-glutathionyl-7,9,11-$\text{trans}\text{-14-}\text{cis}\text{-eicosatetraenoic acid (11-}\text{trans}$ leukotriene C, previously referred to as leukotriene C-2) by ultraviolet spectroscopy, amino acid analyses, lipoxygenase conversion and comparisions with a synthetic compound of known structure and stereochemistry.     

Identification of a component of rat mononuclear cell SRS as leukotriene D

Slow reacting substance (SRS), produced by rat peritoneal mononuclear cells after stimulation with ionophore A23187, consists of two main components (Bach, M.K. et al. (1979) J. Immunol. 122, 160–165). One of these components was recently identified as leukotriene C-1. The other component has now been identified as leukotriene D.     

L-3-Phosphoglyceric acid,formed by ribulose-1,5-bisphosphate carboxylase,is the primary substrate for photorespiration: Experimental test of a hypothesis

Preparations of RuBP carboxylase are shown to carry out an oxygen dependent decarboxylation of L-3-phosphoglyceric acid. The product of this reaction is probably phosphoglycollate. L-3-phosphoglyceric acid, formed by RuBP carboxylase is therefore proposed to be the primary substrate for photorespiration.     

Periodate oxidation and alkaline degradation of heparin-related glycans

Heparin, heparan sulphate, and various derivatives thereof have been oxidised with periodate at pH 3.0 and 4° and at pH 7.0 and 37°. Whereas oxidation under the latter conditions destroys all of the nonsulphated uronic acids, treatment with periodate at low pH and temperature causes selective oxidation of uronic acid residues. The reactivity of uronic acid residues depends on the nature of neighbouring 2-amino-2-deoxyglucose residues. d-Glucuronic acid residues are susceptible to oxidation when flanked by N-acetylated amino sugars, but resistant when adjacent residues are either unsubstituted or N-sulphated. L-Iduronic acid residues in their natural environment (2-deoxy-2-sulphoamino-d-glucose) are resistant to oxidation, whereas removal of N-sulphate groups renders a portion of these residues periodate-sensitive. Oxidised uronic acid residues in heparin-related glycans may be cleaved by alkali, producing a series of oligosaccharide fragments. Thus, periodate oxidation-alkaline elimination provides an additional method for the controlled degradation of heparin.     

Complexing of glycofuranosides with calcium ion,and its effect on their acid-catalysed solvolysis

Stability constants for the calcium-ion complexes of several methyl aldo-furanosides have been determined in aqueous solution by using a potentiostatic technique with an electrode that is selective for calcium ions. The results obtained have been verified by examining the chromatographic behaviour of the compounds on a strong cation-exchange resin in the Ca²⁺ form. The rate constants for the acid-catalyzed hydrolysis and methanolysis of a few 4-chlorophenyl aldofuranosides having different complexing abilities have been determined at various concentrations of calcium chloride. The dependences of the observed salt effects on the complexing ability of the substrate are discussed.     

Correlation of the effect of feeding upon the cell cycle distribution profiles of MPC-11 cells with the relative appearance of [3H]-choline labeled material in microsomal subfractions and other cell fractions

Summary Cultures of mouse plasmacytoma cells (MPC-11) grown within the range 6–23 × 10⁵ cells/ml showed considerable variation in cell cycle distribution profiles and also differences with regard to relative amounts of microsomal subfractions. The variability of appearance of heavy rough (HR) and light rough (LR) microsomal subfractions was not merely due to differences in nutritional state of the culture. Cultures containing a high S/G₂ + M cell cycle distribution ratio showed a high content of HR microsomal membranes; as the S/G₂ + M ratio decreased, so too decreased the amount of HR material whilst the amount of LR microsomal membranes increased. The results indicate that there is a direct correlation between phase of cell cycle and both amount and relative distribution of rough microsomal membranes, the smooth fraction (S), however, remains relatively unchanged.     

Haematological studies on90Sr-90Y-toxicity

Summary Erythropoietic changes were observed, measured by⁵⁹Fe-uptake into red blood cells, and on radioiron turnover from blood plasma, at different time intervals (2–64 days) after treating adult female mice with varying activities of⁹⁰Sr-⁹⁰Y. Activities of 2.5 or 5.0 µCi radiostrontium per animal lead to a depression at time intervals of two and four days, at longer periods there was an overshoot. With activities of 0.5 or 1.0 µCi radiostrontium disturbances in the radioiron uptake are still observed, although these effects are not as pronounced as in experiments with higher burdens. In comparison with results obtained in experiments in which the plasma⁵⁹Fe-turnover was applied, even with an activity of 5 µCi radiostrontium per mouse, no deviation as against the untreated controls was detected.Dedicated to Prof. Dr. Hermann Muth, Homburg/Saar, on the occasion of his 65th birthday     

Pronounced inhibition of noradrenaline uptake by 10-hydroxymetabolites of nortriptyline

The potency of the tricyclic antidepressant nortriptyline (NT) relative to that of its major metabolite (E-10-hydroxynortriptyline; E-10-OH-NT) to inhibit the uptake of noradrenaline in rat brain slices incubated in human plasma was 1.75 ± S.D. 0.30. The E- and Z-isomers of 10-OH-NT were equipotent. Hydroxy-metabolites of NT or amitriptyline did not inhibited the neuronal uptake of serotonin.During treatment of 87 patients with NT or amitriptyline the mean ratio between the plasma levels of unconjugated 10-OH-NT and NT was 1.40 ± S.D. 0.86 with a range of 0.32 – 5.0. This ratio increased with age. There was a significant correlation between the plasma levels of the two compounds (r = 0.63; p < 0.001). In three patients treated with NT, the CSF levels of the parent drug and unconjugated 10-OH-NT were similar and about 5 % of the plasma levels.These results indicate that during treatment with NT (or amitriptyline) 10-OH-NT contributes to the effect of these drugs on central noradrenergic neurons. This seems to be of special significance in the elderly.     

A small-scale saturator for experiments in which a high accuracy in humidity is required

Summary A saturator of small dimensions is described. Moist air with dewpoint temperatures ranging from 2°C to 30°C with a long-term stability of ±0.05°C and a maximum output of 400 1/h can be attained.Special attention is paid to the calibration procedure and to the effect of the reduction of dewpoint temperature of moist air flowing through a tube.     

Water permeability of plant cuticles: The effect of temperature on diffusion of water

The effect of temperature on water permeability of plant cuticles (astomatous Citrus leaf cuticles) has been investigated. The Arrhenius plot (logarithm of the permeability coefficient vs. 1/temperature) has two linear portions that intersect at 44° C. Evidence is presented to show that this intersection represents the solid/liquid phase transition of cuticular lipids. As the Arrhenius plot has only one phase transition in the temperature range of 5 to 80° C, it appears that all soluble cuticular lipids in the cuticle are present as a homogeneous mixture rather than as individual layers differing in composition. This view is supported by electron spin resonance evidence showing homogenous distribution of spin label fatty acids. The original distribution of soluble cuticular lipids is irreversibly altered by heating cuticular membranes above the transition temperature. This is accompanied by an irreversible increase in water peremeability, demonstrating the importance of the structure of cuticular lipids with regard to cuticular permeability.Abbreviations CM cuticular membranes - MX polymer matrix - SCL soluble cuticular lipids - MES morpholinoethane sulphonic acid - J flux - ESR electron spin resonance - THO tritiated water