Reduced foetal calcium without skeletal malformations in rats following high maternal doses of a strontium salt

Zusammenfassung nachweis, dass hohe Strontiumkonzentrationen die Kalzifikation der, Knochen neugeborener Mäuse, und diejenige in Knochengewebskulturen hemmen. Im Gegensatz dazu und zu anderen knochenaffinen metallen wirkt Strontiumnitrat in Dosen von25, 50, 100 and 200 mg/kg, verabreicht während des 9. bis 19. Trächtigkeitstages, bei Ratten nicht teratogen.

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We are indebted to Mr.K. L. Murray of the Government Chemist's Laboratory for analyzing tissue samples by atomic absorption spectrophotometry. We are also grateful toDr. R. F. Crampton, Director of BIBRA, for his interest and advice in this work.     

14-3-2 protein in rat brain synapses

Summary The distribution of the 14-3-2 protein in rat brain synapses was studied by immuno electron microscopy. The protein was localized to the postsynaptic web and to the postsynaptic membrane, but was also prominent both in the presynaptic membrane and in the presynaptic densities. No significant activity was observed in the synaptic vesicles.Acknowledgments. Our sincere thanks to Mrs Ulla Svedin, Eng., for skilled technical assistance. This work was supported by grants from the Swedish Medical Research Council, the Medical Faculty of Göteborg, Tore Nilson's Foundation for Medical Research and by the Swedish-Italian Group of Neurobiology. A. G. received financial support from Consiglio Nazionale delle Ricerche (CNR, ROME).     

The lymphatic route. 1) Albumin and hyaluronidase modify the normal distribution of interferon in lymph and plasma

Summary When human recombinant interferon-₂ diluted in saline was injected s.c. into rabbits, the total amount recovered in thoracic lymph was less than 0.4%. Recoveries increased from 2- to 8-fold if interferon was injected in 4% albumin or with hyaluronidase, respectively. Albumin added to interferon acts as an interstitial fluid expander, thus favoring interferon absorption through lymphatics rather than blood capillaries. This strategy may increase the therapeutic index of interferon.This work was supported by Ministero Pubblica Istruzione and Progetto Finalizzato Oncologia, contract No. 84.00461.44, CNR, Roma.     

Photon emission from normal and tumor human tissues

Photon emission in the visible and near ultraviolet range by samples of human tissue removed during surgery has been measured by means of a low noise photomultiplier coupled to a data acquisition system. The results show that among the 25 analyzed samples the 9 from normal tissues had an emission rate of the order of some tens of photons/cm² min, while most of the 16 tumor tissue samples had a very much higher rate.     

Intermittent dislocation flow in viscoplastic deformation

The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated 'dislocation dynamics' simulations have proved very effective in the study of dislocation patterning, and have led to macroscopic constitutive laws of plastic deformation. Yet, a statistical analysis of the dynamics of an assembly of interacting dislocations has not hitherto been performed. Here we report acoustic emission measurements on stressed ice single crystals, the results of which indicate that dislocations move in a scale-free intermittent fashion. This result is confirmed by numerical simulations of a model of interacting dislocations that successfully reproduces the main features of the experiment. We find that dislocations generate a slowly evolving configuration landscape which coexists with rapid collective rearrangements. These rearrangements involve a comparatively small fraction of the dislocations and lead to an intermittent behaviour of the net plastic response. This basic dynamical picture appears to be a generic feature in the deformation of many other materials. Moreover, it should provide a framework for discussing fundamental aspects of plasticity that goes beyond standard mean-field approaches that see plastic deformation as a smooth laminar flow.     

The insulin-degrading enzyme is an allosteric modulator of the 20S proteasome and a potential competitor of the 19S

The interaction of insulin-degrading enzyme (IDE) with the main intracellular proteasome assemblies (i.e, 30S, 26S and 20S) was analyzed by enzymatic activity, mass spectrometry and native gel electrophoresis. IDE was mainly detected in association with assemblies with at least one free 20S end and biochemical investigations suggest that IDE competes with the 19S in vitro. IDE directly binds the 20S and affects its proteolytic activities in a bimodal fashion, very similar in human and yeast 20S, inhibiting at (IDE)?≤?30 nM and activating at (IDE)?≥?30 nM. Only an activating effect is observed in a yeast mutant locked in the “open” conformation (i.e., the α-3ΔN 20S), envisaging a possible role of IDE as modulator of the 20S “open”–”closed” allosteric equilibrium. Protein–protein docking in silico proposes that the interaction between IDE and the 20S could involve the C-term helix of the 20S α-3 subunit which regulates the gate opening of the 20S.     

Inhibition of local connective tissue repair in the neoplastic response to water soluble carcinogens administered subcutaneously

Zusammenfassung Nach subkutaner Injektion einiger sogenannter wasserlöslicher Karzinogene (N-Methyl-N-Nitrosoharnstoff, Nitroquinolin-N-Oxyd und Butyryl-ethylenimin) erfolgt eine lokale Nekrose der subkutanen Gewebe mit verzögerter Regenerierung des Bindegewebes.