Human synoviocytes: activation and desensitization by prostaglandins and 1-epinephrine

The human synoviocyte increases its intracellular adenosine 3':5'-cyclic monophosphate (cAMP) concentration significantly after incubation with prostaglandin E1, prostaglandin E2, or l-epinephrine. The cells can be desensitized to these same hormones. Hormone-induced desensitization is receptor site specific and associated with a significant increase in intracellular 3':5'-cyclic AMP phosphodiesterase (EC 3.1.4. 17; 3':5'-cyclic AMP 5'-nucleotidohydrolase) activity, whereas cAMP-induced desensitization is not hormone specific.

Conversion of histidine to hercynine by Neurospora crassa

Cell-free extracts of Neurospora crassa mycelium catalyze the methylation of l-histidine to form hercynine (histidine betaine). The partially methylated compounds, alpha-N-methyl-l-histidine and alpha-N,N-dimethyl-l-histidine, are also methylated by the same enzyme preparation to form hercynine. All three methylation reactions are stimulated by the addition of S-adenosylmethionine.

Magnetic Properties of the Lunar Crystalline Rock and Fines

Magnetic measurements have shown that nondiamagnetic minerals in a lunar crystalline rock of type B are (free Fe(2)+ in paramagnetic pyroxenes) : (antiferromagnetic FeSiO(3)) : (antiferromagnetic FeTiO(3)) : (ferromagnetic iron) = 4.3 : 7 : 20 : 0.08 in weight percentage. The abundance of ferromagnetic Fe in the lunar fines is about 7.5 times its abundance in the crystalline rock. The natural remanent magnetization of the crystalline rock of 7.5 x 10(-6) emu/ g in intensity may not be attributable to its thermoremanent magnetization.