Effect of ricin,of its subunits and of modeccin on cAMP level in Yoshida ascites cells

Summary The B chain of ricin strongly decreases the PGE₁-enhanced level of cAMP in Yoshida ascites sarcoma cells, whereas the A chain is ineffective. Modeccin does not have any effect.Acknowledgments. We thank E. Lorenzoni for preparing ricin and modeccin. The work was aided by a contract from The Consiglio Nazionale delle Ricerche, Rome, within The Piano Finalizzato Controllo della crescita neoplastica and by Pallotti's legacy for cancer research.     

Effects of DL-propranolol on exercise heart rate and maximal rates of oxygen consumption inScaphiopus intermontanus

Summary Lymphatic injection of propranolol (0.2–10 g) into toads decreased exercise heart rate in a dose-dependent manner. There was a significant linear corrleation between exercise heart rate and maximal oxygen consumption rates . These data are consistent with the hypothesis that blood oxygen transport is the limiting process for max in anuran amphibians.This work was supported by a grant from the National Science Foundation (PCM-8021808). I am grateful to Dr P.C. Withers for logistical support and Dr S. Yokota for the initial idea.     

Neurogenic responses of resistance and capacitance vessels

- . , , , . , .     

Effect of radical scavengers on TNFα-mediated activation of the uPA in cultured cells

Active oxygen, produced by cultured cells following stimulation with various growth factors, seems to be involved in signal transduction leading to cellular responses such as gene expression and growth modulation. In the present study, the intracellular oxidation state was measured in immortalized human endothelial cells (ECV304) after treatment with tumor necrosis factor (TNF), using a fluorescent dye and a laser-scanning confocal microscope. The intracellular oxidation state was increased 60 min after the addition of TNF, and this increase was abolished by a radical scavenger, N-acetylcysteine (NAC), which is also a precursor of glutathione, and by pyrrolidine dithiocarbamate (PDTC). TNF increased the steady state level of urokinase-type plasminogen activator (uPA), and NAC inhibited this increase at a dose that also inhibited the increase in the intracellular oxidation state. PDTC, on the other hand, did not affect the induction of the uPA gene by TNF. These results suggest that intracellular glutathione level rather than the oxidation state is necessary for the induction of the uPA gene by TNF.     

The “day of Brahman” in the work of Āryabhata

Summary In the astronomical treatise ryabhatya of ryabhata several verses are interpolated, namely all those verses in which either Brahman was mentioned or extremely large periods were introduced. The interpolator was known to AlBrn as ryabhata of Kusumapura, who belongs to the school of the elder ryabhata. The aim of the interpolator was to bring the teaching of the elder ryabhata into accordance with the revelation of Svayambh. Svayambh is another name for Brahm.     

Studies on rII region of T2L phage

rII T2L , rII T4B. rII T2L rII T4B. T2L rII T4B.     

The stimulating action of gastrin pentapeptide and histamine on adenyl cyclase activity in rat stomach

, 3',5'-, in vitro . , , 3',5'- HCl .     

Luteolytic potency of 16-phenoxy-derivatives of prostaglandin F2α

Summary The binding of 16-phenoxy derivatives of prostaglandin (PG) F₂ to rat luteal membranes, and also their abortifacient potency in pregnant rats, have been studied. Competitive binding studies with various PG-analogues were performed in ovaries of juvenile rats pretreated with PMSG and HCG, and in parallel studies the abortifacient potency of these substances was tested, in pregnant rats. It was observed that this class of derivatives bound to the PGF₂ receptor as well as, or even better than the parent compound PGF₂. Modifications in the carboxyl group at C-1 yielded derivatives with a higher affinity for the receptor, in decreasing order of effectiveness as follows:-COOR>COOH>OH. The data obtained from the binding studies also compared well with data on the abortifacient potency in pregnant rats. It is concluded that the addition of a phenoxy group to either the lower or upper side chain of PGF₂ may augment the binding to the receptor as well as the biological responses induced by the post receptor effect.     

The mechanism of blood vessel permeability derangement under the influence of histamine,serotonin and bradykinin

, , , , 10^–2-10^–3M NaCN . (, ). .     

Complex formation betweenγ-immunoglobulin and calmodulin in calcium-free conditions

We show that -immunoglobulin (IgG) binds calmodulin (CaM) in a Ca²⁺-independent manner, with Kd value of (1.7±0.5)×10^–7M. A single IgG molecule maximally bound 10 CaM molecules. The binding is to the heavy chain or Fab portion, but not the Fc portion, of the IgG molecules. Ca²⁺ greatly diminished the interaction between IgG and CaM, with IC₅₀=8–9M. These data give a novel insight into protein-protein interactions.