Ultrastructure of pulmonary macrophagic system.

A mature AMF, ready for phagocytosis, is a relatively large cell with an oval nucleus, with indentations of a nuclear envelope of varying depth. Evenly distributed chromatin forms beneath the nuclear envelope a rim of heterochromatin. There is a prominent nucleus with a distinct nucleolonemma. The cytoplasm is differentiated into a continuous ectoplasmic zone with numberous finger-like processes and pseudopodia. The organelles are formed by scattered round or oval mitochondria, a description is given of the Golgi apparatus in the juxtanuclear position, in certain sites multifocal in form, of the centriolar apparatus, scarce profiles of endoplasmic granular reticulum, dispersed free polyribosomes and microfilaments in varying amounts. The most outstanding feature is the rich lysosomal apparatus of varying structure depending on the functional state. Dynamics of the maturation of AMF was studied in intermediate phases, described here. The peribronchovascular connective tissue is the seat of free macrophages of a structure analogous with that of AMF. Fixed macrophages are anchored in the loose connective tissue by processes of different shape and length. The prevailing component of the cytoplasm are numerous vesicular structures and vacuoles as well as a marked lysosomal apparatus. Fixed macrophages phagocytize foreign material in situ. The septal cell exists in normal state as an element with numerous intricated processes pervading the fibrillar substrate. Numerous free polyribosomes and vacuoles are its most marked component. Activation of septal cells was demonstrated under experimental conditions. Their transformation into free macrophages is probable. In the pulmonary intersitium, in the perivascular loose connective tissue particularly free cells of a similar structure as blood monocytes were shown in normal state. Under experimental conditions an increased number of monocytes is present in pulmonary capillaries, e.g. 24 hours after an intratracheal instillation of India ink colloid solution. At the same interval a number of free cells of the monocyte structure was found in the perivascular connective tissue and also in the alveolar lumen, with phagocytized carbon. An increased number of monocytes transforming into macrophagic cells was visualized in this localization as late as 14 days after the instillation of India ink colloid solution. The experimental study with an intratracheal instillation of India ink colloid solution in the mouse gave evidence of a high readiness of AMF. The carbon particles were seen phagocytized at an interval of 5 minutes after instillation. In all intervals during which free carbon particles were present in the alveolar epithelium mature AMF were observed with no or very low phagocytic activity, their lysosomal apparatus being prominent. On the contrary, in the phagocytizing AMF, the lysosomal apparatus disappeared in the greatest part of the cytoplasm. The clearance of AMF occurs predominantly by the air route...

The ultrastructure of the tracheal epithelium in European common lizard (Lacerta agilis L.) and in sand lizard (Lacerta vivipara Jacq.).

This study describes the ultrastructure of the tracheal epithelium in the European Common lizard (Lacerta agilis L.) and in the Sand lizard (Lacerta vivipara Jacq .). The main attention is paid to the granular cells of secret-producing type, which form the substantial part of this epithelium and which were observed for the first time in the house gekko . Contrary to the findings in house gekko , in the representatives of the genus Lacerta 2 types of electrondense granules were observed. One type is homogeneous and lighter in colour, the other is darker with lamellar pattern. Among other elements, the ciliated cells as well as basal and plasmatic cells were found. In both species we also succeeded in proving the presence of isolated neurosecret -producing cells.

[Ultrastructure of the air-blood-intestinal respiration barrier of the American sheatfish Hoplosternum thoracatum]. / Die Ultrastruktur der Luft-Blut-Darmatmungsbarriere des amerikanischen Welses Hoplosternum thoracatum.

The fish, Hoplosternum thoracatum, lives in water with a permanently reduced content of oxygen. The respiratory gut as an accessory respiratory organ makes it possible to breath atmospheric oxygen and facilitates gaseous interchange. It forms a large, dilated tube containing a voluminous bubble of air. The wall of the respiratory gut is extremely thin. Below the peritoneum there is situated a branching plexus of blood vessels. The tributaries extent perpendicularly and reach the epithelium. They form a rich anastomosing capillary network. The capillaries are covered with attenuated processes of squamous epithelium. The thickness of epithelial processes ranges roughly from 0.5-1.0 micron. The basal part of the respiratory epithelium is lined with basal lamina which, in many places fuses with basal lamina of the capillary endothelium. The air-blood barrier of the respiratory gut is, in principle, built up according to the known general bauplan and is formed by thin epithelial and endothelial components and complex of basal laminae. The nonrespiratory area of the gut is lined with columnar epithelium of enterocyte type.