Tuftsin and D-Arg3-tuftsin possess analgesic action

Summary Tuftsin has marked analgesic activity but is less potent than D-Arg³-tuftsin. The absence of an antagonistic effect of naloxone on tuftsin and its analogue suggests that these substances do not act on opiate receptors. Tuftsin and its analogues may represent a new class of substances of interest in the search for new analgesics.     

Studies on the role of phenethylamine in methylamphetamine action mechanisms

Summary According to our results, we think that the tolerance developed to central effects of N-methylamphetamiee are caused by the liberation and posterior depletion of phenethylamine from its storage places, which is in agreement with our hypothesis about the action mechanisms of amphetamines in the central nervous system.     

Radioprotective thermally generated free-radical dextrins

Effect of doses of the X-ray radiation from 0 to 400 Gy upon granular cornstarch and dextrins （British gums, BG） thermally generated from it at 230--300℃ was recognized with quantitative EPR and IR absorption spectroscopy, molecular mass distribution in the depolymerization products, Scanning Electron Microscopy, and X-ray diffractometry. Fractal analysis of the profiles of molecular mass distribution showed that the depolymerization involved debranching of amylopectin. Roasting of cornstarch produced BG which differed in concentration and EPR parameters of stable free radicals from BG generated by X-ray radiation. Two types of stable free radicals, with Gaussian and Lorentzian shapes of EPR signals, were recognized. The shapes of the signals and temperature dependence on free radical intensity indicated exchanging interactions of the antiferromagnetic type, causing partial quenching of the spins at-196℃（77K）. Upon X-ray irradiation, new radicals were generated, the number and stability of which strongly depended on the types of radicals present before irradiation. These radicals slowly ceased because of a repolymerization of BG on storage.     

Role of catecholamines in thyroxine-induced changes in metabolism and body temperature during exercise in dogs

Summary Blockade of beta receptors inhibited thyroxine-induced increases in T_re, blood FFA and LA levels during exercise in dogs.     

N-dimethylated indoleamines in blood of acute schizophrenics

Resumen En nuestros estudios en sangre de esquizofrenicos agudos, hemos encontrado, usando cromatografia en capa delgada y cromatografia gaseosa liquida, dimetiltriptamina, y 5-metoxi-N, N-dimetiltriptamina. En solo uno de ellos hallamos bufotenina. Estas substancias no fueron detectadas en nueve esquizofrenicos cronicos, dos normales y un enfermo depresivo.     

Essential Tension: Mathematics - Physics - Philosophy

The author focuses on the tension "realism - idealism" in the philosophy of mathematics, but he does that from the perspective of a theoretical physicist. It is not only that one's standpoint in the philosophy of mathematics determines our understanding of the effectiveness of mathematics in physics, but also the fact that mathematics is so effective in physical sciences tells us something about the nature of mathematics.     

Crystal structure of the FimD usher bound to its cognate FimC-FimH substrate

Type 1 pili are the archetypal representative of a widespread class of adhesive multisubunit fibres in Gram-negative bacteria. During pilus assembly, subunits dock as chaperone-bound complexes to an usher, which catalyses their polymerization and mediates pilus translocation across the outer membrane. Here we report the crystal structure of the full-length FimD usher bound to the FimC-FimH chaperone-adhesin complex and that of the unbound form of the FimD translocation domain. The FimD-FimC-FimH structure shows FimH inserted inside the FimD 24-stranded β-barrel translocation channel. FimC-FimH is held in place through interactions with the two carboxy-terminal periplasmic domains of FimD, a binding mode confirmed in solution by electron paramagnetic resonance spectroscopy. To accommodate FimH, the usher plug domain is displaced from the barrel lumen to the periplasm, concomitant with a marked conformational change in the β-barrel. The amino-terminal domain of FimD is observed in an ideal position to catalyse incorporation of a newly recruited chaperone-subunit complex. The FimD-FimC-FimH structure provides unique insights into the pilus subunit incorporation cycle, and captures the first view of a protein transporter in the act of secreting its cognate substrate.