Rhein as an electron acceptor for various flavoproteins and for electron transport particles.

Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid) which has been previously employed as an inhibitor for electron transport particles, NADH dehydrogenase, and other flavoproteins is reducible under physiological conditions. Soluble hydrogenase from Alcaligenes eutrophus H 16, several flavoproteins, and electron transport particles from baker's yeast and from beef heart were found to catalyse NADH oxidation with 9 micrometers to 2mM rhein as the electron acceptor. Dithionite or enzymatically reduced rhein (lambda max = 408 nm) is immediately reoxidized to rhein lambda max = 437 nm) by oxygen.

[Sleeping behavior between the ages of 2 and 18. Longitudinal study].

Sleeping behavior was investigated in 320 Swiss children 2 to 18 years of age. The data were based on the First Zurich Longitudinal Study (1954-1980). The incidence of resistant behaviour at bedtime increased from 8 to 40% between age 2 and 10.

[Quantitative whole-body bone scintigraphy. II. Pharmacokinetics of osteotropic radiopharmaceuticals (author's transl)].

85Sr, 99mTc-Sn-pyrophosphate and 99mTc-Sn-methylene-diphosphonate, the most important agents for skeletal imaging, are compared with each other by calculation of the plasma clearance and the urinary excretion and by a series of quantitative whole-body scans. 85Sr the distribution volume in equilibrium is the largest, shifting of activity is demonstrable for several days after injection. 99mTc-Sn-MDP is excreted most quickly, equilibrium is reached early.

Rapid colorimetric analysis of chlorhexidine in pharmaceutical preparations.

A colorimetric determination of chlorhexidine is described. The method is based on the formation of a yellow complex between the drug and bromcresol green. The absorption peak of this complex, extracted by chloroform, is at 410 nm, and linear response is obtained from 2.

Metabolic behaviour and cleavage capacity in the amphibian egg.

During the winter season the full grown Bufo arenarum oocyte shows the metabolic behaviour characteristic of differentiated tissues of the same species. Due to seasonal variations, during the amplexus period, it acquires the metabolic behaviour of the segmenting egg. Short-time-induced ovulations (5-6 h) determine germinal vesicle breakdown immediately before the expulsion of the oocyte, without modifying the ovarian metabolism of the same.