On the formation of the myotomes in avian embryos. An experimental and scanning electron microscope study

Summary The formation of the myotomes to chick embryos was studied by using experimental and scanning electron microscope techniques. With the aid of the quail-chick marker system, it was demonstrated that the dermatome gives rise to the myotome plate. SEM studies support the conclusion that the myotome cells originate only from the edges of the dermatome.Supported by the Deutsche Forschungsgemeinschaft (Ch 44/2).     

Fusion of microsomal vesicles

Summary Studies which indicate the fusion of rat liver microsomal vesicles show that the rate of fusion of microsomal vesicles, as revealed by electron microscopic examinations, is dependent on the fusion temperature and the amount of detergent present in the microsomal suspension.Acknowledgments. We thank Miss R. Kannler for excellent technical assistance. The electron microscopy was performed in Anatomisches Institut and the Strahlenzentrum of the University of Giessen. This investigation was supported by the Deutsche Forschungsgemeinschaft (Schu 54/5) and by the Stiftung Volkswagenwerk (AZ 11 2454).     

Respiratory function of blood and relative weight of certain organs in two species of shrew: Crocidura russula and Suncus etruscus (Soricidae mammals)]

A high oxygen capacity combined with a low oxygen affinity and a large Bohr effect achieve a high oxygen transport capacity in small shrews. The high metabolic rate (Suncus estruscus: 100 to 350 ml O2/kg. min) can be explained by the combination of the favorable blood parameters with a high relative heart weight (1,2% of body weight) and heart frequencies of 1,000 to 1,350 per minute.     

Prostacyclin-like activity of endothelium and subendothelium — important for atherosclerosis?

Summary Morphological control of Moncada's bioassay for prostacyclin (PG I₂) activity measurement shows that the activity depends not only on endothelium, but in important amounts on subendothelial tissue too. Therefore, it can be concluded that platelet thrombus formation after endothelial cell injury does not depend only on the PG I₂-producing ability of the tissue.     

Neurophysiological basis of directional hearing in amphibia

Discrete regions of neural tissue along the anterior-posterior axis of the torus semicircularis act as resonators, each one broadly tuned to a different range of frequencies, and each one responding optimally to the incident sound from a different direction. In this way, a map of auditory space is represented in the midbrain.