Collagen in the aortae of spontaneously hypertensive (SHR) rats.

A biphasic pattern of collagen biosynthesis was found in the aortae of spontaneously hypertensive (SHR) rats; the time course of the rate of biosynthesis is similar to that described in the heart by Sen and Bumpus. In comparison to age-matched controls, collagen biosynthesis is elevated in the SHR rats, diminishes during the first fourteen weeks and rises again at the stage of established hypertension. In the period of established hypertension, the increased rate of collagen biosynthesis was associated with a pronounced rise of the collagen type I to type III ratio. On the other hand, in the pre-hypertensive stage, the proportion of collagen type III clearly exceeds the proportion of collagen type I in SHR rats.

Collagen and elastin synthesis in the aorta of spontaneously hypertensive rats.

The biosynthesis of collagen and elastin was followed during the development of spontaneous hypertension in rats (SHR) of the Okamoto-Aoki strain. Strain-matched animals of the same age, which did not develop hypertension, served as controls. Both collagen and elastin synthesis (as revealed by specific hydroxyproline activity) was found to exceed control levels in the prehypertensive period, to decrease during the development of hypertension and to increase again in the period of the established hypertensive state. From the two main collagen types present, synthesis of collagen type III exceeded that of type I in the prehypertensive period (at the age of 4 weeks) and this relation was reversed during the period of established hypertension. It is suggested that (a) the vascular connective tissue metabolism in SHR differs from that in strain-matched controls, and (b) the reverse rate of collagen type III to collagen type I synthesis during hypertension development may be considered an adaptive response to the increasing pressure load which may alter the mechanical properties of the vessel wall.

Colchicine-induced appearance (proliferation) of smooth sarcoplasmic reticulum in arterial smooth muscle cells.

Colchicine treatment resulted in the appearance and proliferation of smooth sarcoplasmic reticulum in some smooth muscle cells of the aortic and pulmonary trunk walls in the rabbit. The significance of cytoplasmic microtubules and/or membrane-bound tubulin for the morphogenesis, functioning and control of smooth endoplasmic reticulum in different kinds of cells is discussed.

Association of smooth membranes with spindle microtubules in the arterial smooth muscle cell.

Smooth membrane-limited vesicles and cisternae are closely associated with spindle microtubules in mitotic pulmonary trunk smooth muscle cells of the rabbit. This may play a regulatory role in the structure-function integrity of the spindle.

[The morphological bases of transcapillary metabolism in the adrenal cortical layer]. / Morfologicheskie osnovy transkapilliarnogo obmena v korkovoi chasti nadpochechnika.

Capillaries of the cortical substance in the white rat adrenals have been studied by means of electron microscopic and tracing methods. Two types of interendothelial contacts-the adhesive and occlusive have been described. Owing to the identification of the open and close micropyknocytic vesicles, it has been stated that the vesicular transport through endothelium takes place simultaneously in both directions. Transendothelial canals occur rather seldom. Molecules of ferritin get into them. Fenestrae occupy the greater part of the endothelial cells. Position and size of the fenestrae are described, as well as the structure of their diaphragm. The fenestrae have been stated to be permeable for molecules of ferritin. Owing to their structural peculiarities and the experiments on ferritin administration, the interendothelial contacts are identified as structural equivalents of small pores, previously described by physiologists, and the micropyknocytic vesicles, transendothelial canals and fenestrae-as structural equivalents of large pores. At some small areas, the endothelium can be interrupted, evidently, as consequence of certain rearrangements of the fenestrated area resulted from an increased transcapillary transport.

[Ultrastructural similarities of secretory processes in arterial smooth muscle cells and elastic cartilage chondrocytes. vacuolar apparatus and microtubules (author's transl)]. / Ultrastrukturelle Parallelen der Sekretion in glatten Muskelzellen von Arterien und Chondrozyten des elastischen Knorpels. Vakuolärer Apparat und Mikrotubuli.

A highly developed vacuolar apparatus is found in aorta and pulmonary trunk smooth muscle cells and elastic cartilage chondrocytes, and its relationship with cytoplasmic microtubules is described. The Golgi complex as well as the rough endoplasmic reticulum (RER) may be the intracellular sources of the components of the vacuolar apparatus. Some vacuoles, Golgi-related only, showed an association with microtubules. Smooth muscle cells which contained vacuoles derived from RER did not possess Golgi vacuoles and microtubules. In chondrocytes, both Golgi-related and RER vacuoles coexisted in a single cell. 2 main secretory pathways are suggested to operate in smooth muscle cells and chondrocytes: Golgi and RER pathway. The former requires an intact cell tubulin system (cytoplasmic microtubules and membrane-bound tubulin), while the latter is probably microtubule-independent.

[Ultrastructural mechanisms of transendothelial transport in blood vessels]. / Ultrastrukturni mekhanizmi na transendotelniia transport v kruvonosnite sudove.

The author describes a series of structural aspects of transendotheliumiumial transport on the basis of literary data, printed in journals and coming from well known foreign laboratories. He reports data on three types of endothelium--uninterrupted, fenestrated and interrupted. He indicates the ways of transfer of lipid-soluble substances and ultrastructural devices for transfer of water and water-soluble substances. These devices are divided into two groups-universal (vesicular structures, intercellular slits), which are characteristic of the three types of endothel and specific (fenestra and pores), characteristic of fenestrated and interrupted endothel respectively. The author presents a series of actual questions about vesicular transport-nature and movement of micropinocytotic vesicules, structure, permeability and orientation of transendothelial canals. He describes data on possibility of intercellular slits as sites for passive transport of water and water-soluble substances. He indicates distribution and structure of binding complexes between endothelial cells, limiting permeability of intercellular contacts. The structure and permeability of fenestra and pores are presented as sites of passive transport, but those of the pores-for active passage of cellular elements as well. Various ultrastructures, connected with endothelial permeability, are surveyed as morphologic equivalents of the small or large pores by the physiological theory of pores.

[Ultrastructural aspects of the transendothelial passage of macromolecules in the pulmonary trunk of the rat]. / Niakoi ultrastruktuni aspekti na transendotelniia pasazh na makromolekuli v belodrobniia stvol na plukh.

The authors examined the transendothelial passage of tracer macromolecules (feritin) in the endothelial cells of the lung stem of white rats (Wistar) by means of an electron microscope. They found that the feritin granules were detained by the pilous surface of the luminal cytolema at the initial phase of the process. This was enhanced also by luminal buds and invaginations respectively paraluminal canals, functioning as stagnating devices. The uptake and transcellular passage of the macromolecules was realized by micropinocytose vesicules, part of which were intracellularly and formed vacuole depots. Vesicules were formed from them secondarily, carrying the tracer mainly basaly. The authors observed also a bead roll pattern of transport vesicyles, which, passing tracer molecules one to another, formed functional trancellular canals for quick transport. There were certain dependences between the established forms of trancellular passage and the circulation time of feritin.

[Ultrastructural manifestations of the secretory function of the chondrocytes in elastic cartilage]. / Ultrastrukturni proiavi na sekretornata funktsiia na khondrotsitite v elastichniia khrushtial.

The authors examined ultrastructural manifestations of the secretory function of chondrocyetes in the auricular tendon of rats. They found that chondrocyetes were active secretorily in the prenatal and early postnatal ontogenesis; in later age such activity possessed mainly those chondrocytes located subperichondricaly. The existance of direct communications of cysternas of the granulated endoplasmic reticulum with extracellular area was interpreted as a possibility for direct release of the secretory products. Small coated vesicules with dense content were followed-up from the Goldi's organs till their openings on the cellular surface. Two types of vacuoles were differentiated-some with optically dense content, localized in the Goldi's organs, and others-optically empty, which were encountered in their boundaries as well. A concept was given that the first type originates from the granulated endoplasmic reticulum and transported protein product, but the second type-from the Goldgi's complex and transported probably polysaccharides.