Ultrastructural autoradiographic study of the intracellular fixation of 3H-acrolein.

The fixation of 3H acrolein in Dunaliella bioculata was followed by means of quantitative autoradiography electron microscopy. A fixation was observed mostly in the nucleus where aldehyde linkage remained stable at least for 48 hours.     

Are anticholinergic effects responsible for the heterogeneous quinidine-induced modifications of heart muscle refractoriness?

Cellular and Molecular Life Sciences - Vagal tone is responsible for the heterogeneous reactivity of atrial and ventricular contractile tissues to quinidine. Acetylcholine may make atrial cells...     

Myosin isoenzymes during in vivo and in vitro differentiation of chick muscles

Muscle fibers differentiated, in vitro, from myoblasts of embryonic Pectoralis (presumptive fast) and embryonic Adductor magnus (presumptive slow) muscles synthesise the same type of myosin, which is identical to the type synthesised in day 10 embryonic muscles. This type of myosin comigrates with the third isozyme of the adult fast-twitch muscle. There is no change in the kind of myosin in cultures aged from 2 to 7 weeks, whereas during the in vivo differentiation of the same muscles, new isozymes appear which are different in the two muscles. With regard to myosin, the muscle fibers differentiated, in vitro, from myoblasts of fast or slow muscles expressed the same phenotype.     

Variation in the toxicity of various silicas in relation to the duration of presence in the body]

The toxic effect of two forms of sand on the lung was investigated by tracheal injection in Rats. After a latent period with low toxicity, more and more extensive pulmonary lesions, comparable to typical silicotic lesions, appear progressively. On the basis of some observations, the hypothesis is put forward that the impurities present in the dust have a retardative effect.