Comparative studies of seed proteins of the genusArtocarpus with respect to lectins

Proteins from two species of the genusArtocarpus (A. integrifolia L. andA. incisa L.) were compared by ammonium sulphate fractionation, molecular sieve chromatography and SDS-polyacrylamide gel electrophoresis, with special attention to the lectins. The protein content and hemagglutinating activity were markedly different in the two seeds. The protein pattern obtained by both molecular sieve chromatography and SDS-polyacrylamide gel electrophoresis were quite different. The only similarities found were the elution volume of the lectins in the Sephadex G-100 column and the lectin bands (11 500 and 15 000 daltons) in SDS-polyacrylamide gel electrophoresis.     

Epithelial transport parameters: an analysis of experimental strategies

A set of experiments was simulated on a computer version of the Koefoed-Johnsen & Ussing model for high-resistance epithelia. The results obtained were analysed according to procedures commonly applied to the analyses of experimental data and interpreted in terms of the model parameters. Although the computer model encodes a stoichiometry of 3:2 for Na-K exchange through the Na pump, the simulation of published experimental procedures yields different figures in almost every case. We show that ENa as originally defined by Ussing & Zerahn (Acta physiol. scand. 23, 110-127 (1951)) and as obtained from flux-ratio experiments has different values under different experimental conditions with unchanged system parameters and that it is distinct from ENa measured by other methods. We also show that unless the pump is saturated with internal Na an increase in the rate of pumping cannot cause a substantial increase in the rate of transepithelial Na transport.     

Children's Hospital Admissions and Mother's Menstruation

Of 100 children''s emergency admissions to hospital nearly half (49%) were admitted during the mother''s paramenstruum. There was a statistically significant association between the mother''s menstruation and the child''s admission both for accidents and for illnesses. The eldest child in the family appeared to be most affected.     

Frictional coefficients of multisubunit structures. I. Theory

The theory of Kirkwood for the translational frictional coefficients of structures composed of subunits has been generalized in two ways in order to consider aggregates of nonidentical subunits. One of these generalizations fails when the sizes of subunits are too disparate; the other, derived from a surface shell distribution of frictional elements, is effective over the whole range of relative sizes. It is shown that, in the limit of a continuous surface distribution, a shell model reproduces Stoke's law for a sphere. Comparison is made between the frictional coefficients of spheres, ellipsoids, and rods modeled by finite numbers of subunits and by continuous shells of frictional elements, and those calculated from other theories. Agreement is generally good, though the shell model for prolate ellipsoids of revolution deviates by a few per cent from the Perrin value.