Cholesterol in the plasmalemma of endotheliocytes in the normal aorta and in hypercholesterolemia (scanning electron microscopy research)

Using a specific latex marker (SLM) and scanning electron microscopy, distribution of cholesterin in plasmolemma of endotheliocytes of the thoracic part of the rabbit aorta has been studied under normal conditions and at experimental atherosclerosis, as well as on the surface of liposomes and flat bilayer films. SLM reacts with a high specificity directly with cholesterin of the membrane. When studying microtopography of cholesterin, it is possible to distinguish microdomains with various density of distribution of SLM particles. Amount of SLM per 1 mcm2 of the artificial membrane surfaces grows at increase of the cholesterin-phospholipid (Ch/Phl) index of the membrane; Ch/Phl can bind with the membranes beginning only with the threshold value of the Ch/Phl index equal to 0.5. At hypercholesterolemia amount of SLM on the luminal surface of plasmolemma of the aortal endotheliocytes increases by 78%. Hence, at hypercholesterolemia in the luminal part of plasmolemma of the aortal endotheliocytes the Ch/Phl index increases; this should be taken into consideration, when observing mechanisms of reorganization of the endothelial cells layer at atherosclerosis.     

Ultracytochemical study of ATP-ase activity in mucosal parietal cells and in the cells of human adenocarcinoma of the stomach]

Ultracytochemical investigation of ATP-ase activity was carried out in parietal cells of the mucosa and in cancer cells of human stomach carcinoma possessing a similar ultrastructure. In parietal cells the reaction product of ATP-ase was observed on the membranes of microvilli of intracellular canaliculi, on the membranes delineating the lateral intercellular space, on the basal plasmolemma and in the nucleoli. The reaction product was absent on the membranes of tubuvesicles and on the apical surface of the plasmalemma. In cancer cells the reaction product was found on the membranes of the microvilli of the intracellular canaliculi, basal plasmolemma and in the nucleoli. Comparative examination of ATP-ase activity in these cells implies that at least the part of the mechanism of hydrochloric acid secretion which is involved in the transfer of H+ and Cl- is retained in cancer cells. A steady decrease in hydrochlorid acid secretion observed in the stomach mucosa in cancer as well as in the tumour itself seems to be associated with other mechanisms.     

Localization of ATPese and Dynamic Change in its Activity within Root Nodules of Legumes

The study on localization of ATP-ase in root nodules of Astragalus sinicus and Sesbania cannabina shows that the particles of lead phosphate precipitates resulting from the reaction of ATP hydrolytic enzyme are distributed in cell wall, plasmolemma, cytoplasm and peribacteroid membranes etc. of the host cells. This ATP-ase plays an important role in the transportation and absorption of substances. Owing to the need of photosynthates provided for the nitrogen fixation of root nodules, the active reaction of ATP-ase in bacteroids varies with their developments. The numbers of bacteroids having ATP hydrolytic enzyme in young root nodules are significantly less than those in senescent nodules. Possibly, this active reaction is related with the physiological function of nitrogen fixation of bacteroids at different development stages.     

Morphofunctional characteristics of the vascular endothelium in the common leech (Clepsina complanta)

The electron microscopic investigation has revealed in the body of the leech two types of vessels, that together with common signs possess a number of peculiarities in composition of endothelial cells. These vessels have different level of organization: the vessels of the first type, concerning the parenchyma of the leech, are nutritive, and the vessels of the second type combine capacitance and transport functions and are the place of hemolymph renovation at the expense of an active metabolic and synthetic activity of the endothelial cells. A fact is stated concerning a specific position of mitochondria in the endotheliocytes of the second type vessels: from the vessel's lumen they are not covered with plasmolemma along their whole extent and come into an immediate contact with hemolymph. Therefore, a hypothesis is suggested on functional activity of the endothelial cell mitochondria in the second type vessels. Presumptive differentiation of the two major vessels of the leech body makes it possible to suppose that there exist functional predecessors of the vessels of branchial and pulmonary type, that is vessels of lesser and greater circulation.     

Functional morphology of the bronchovascular barrier of the human lungs during various age periods

Cellular components of the bronchovascular barrier have been studied in human lungs obtained after death of some patients with acute and chronic lung inflammatory diseases, hypertonic disease, atherosclerosis and chronic glomerulonephritis. Certain oxidative-reductive and hydrolytic enzymes, including NAD-, NADP- diaphorases, lactic dehydrogenase, acid and alkaline monophosphoesterase, ATP-ase, adenylate cyclase and nonspecific esterase were evaluated quantitatively after the histochemical processing of the specimens for the above reactions. Correlation analysis was performed for the bronchial epithelium, endotheliocytes, lymphocytes, plasma and mast cells, as well as macrophages and polymorphonuclear leucocytes. The results showed that there was a significant shift in some of the measured enzymic activities. Moreover, the correlations between different quantitative data were noted and these correlations changed with age. The increase in "rigidity" of the correlations in the elements of the bronchovascular barrier has been demonstrated during the process of ageing.     

Intracellular localization of the multiple forms of ATP-ase activity in maize root tips

Summary The multiple forms of ATP-ase activity in maize root tips have been examined by separation and staining using polyacrylamide gel electrophoresis. The band pattern obtained using a whole homogenate supernatant fraction was compared with the pattern obtained from various cell organelle fractions. The kinetic properties of the ATP-ase activity in various fractions were also examined. The results support the view that ATP-ase activity exists in a number of molecular forms in the same tissue and that these forms may show specific intracellular localizations.     

Microrelief of the internal surface of the thoracic duct in dogs (based on scanning electron microscopy data)

The investigation has been performed on 17 mature dogs. With the aim to investigate the internal surface of the thoracic duct, the methods of scanning electron microscopy of native, impregnated and corrosive preparations have been used. The analysis of the scannograms obtained demonstrates that the valves of the thoracic ducts are mainly bicuspid, have a typical infundibular form, their cuspides are fused, forming a mesentery-like fold on the duct wall. It plays the main role in ensuring unilateral transport of lymph. The microrelief of the thoracic duct endothelium possesses a rather complex organization. The following relief formations are distinguished in endotheliocytes: 1. nuclei-containing eminence, 2. marginal processes, 3. separate microvilli. The dependence of the microrelief on arrangement of endothelial cells in the valvular area or intervalvular fragments is noted. This is also concerned orientation of endotheliocytes; therefore, predominance of stretched endotheliocytes of the postvalvular fragment can be connected with demonstration of viscous friction force in the lymph stream, that produces deforming and orienting influence on the endotheliocytes.     

Quantitative study of the capillaries in a secreting salivary gland (electron-microscopic and morphometric analysis)]

Regularities in structural rearrangement of epithelium of blood capillaries in the rat parotid salivary gland have been studied under various functional conditions of the organ. The data obtained demonstrate that secretion is accompanied by dilatation of anuclear segments of capillary endothelium, decreasing thickness of endotheliocytes, rise of hematocrit number by adding the total area of the capillary fenestrated surface, the form factor of intraendothelial contacts and decreasing length of the contacting cytolemmas. Since extreme values of the metrical parameters studied have been revealed during the phase of the secrete excretion, a suggestion is made that increasing hydraulic permeability of the metabolic vessels with subsequent transport of the fluid to the terminal parts of the gland create the conditions promoting to reach the threshold level of pressure in acini that is necessary to overcome high resistance of nerrow intercalated sections for the secretion to reach the ducts.     

Structure of the endotheliocytes of cerebral vessels of aquatic mammals

By means of scanning microscopy the relief of luminal surface of endotheliocytes, lining microvessels of various parts of the brain in the Pusa sibirica, Phoca vitulina and Delphinapterus leucas have been studied. Specialized formations of the cellular surface--various processes, projections, toruli have been revealed; their character in various parts of the brain in diving animals is determined by the blood stream conditions and their different sensitivity to oxygen deficiency during diving. The peculiarities, revealed in the structure of the cerebral vessels intima, are considered as one manifestations of the adaptive properties in the organism of diving animals, which had been developed in them during the process of a long evolution, while they adapted to the aquatic environment.     

Ultrastructural organization of the aero-hematic barrier of the lungs of laboratory animals

The ultrastructure of the aero-hematic barrier (AHB) of the lungs has been studied in the mostly used laboratory animals-mice and rats. In 2 clinically sound animals in macroscopically unchanged parts of the lungs certain disorders of rheological blood properties have been revealed, edema and focal destruction of endotheliocytes and alveolocytes of the I type, local destruction of the thin part of AHB. The changes revealed in AHB ultrastructure in intact mice and rats are in many respects similar to those developing in the lungs under various extreme influences. Therefore, a wide and thorough investigation of the lung structure in intact animals makes it possible to avoid erroneous conclusions at examining various pulmonary pathology and contributes to a correct estimation of its manifestation degree.     

Formation of primary microvessels in the early stages of prenatal human morphogenesis

By means of light and electron microscopy, the most general mechanisms of formation and development of primary blood microvessels in functionally different organs (adenohypophysis, thyroid, thymus, liver, spleen, small and large intestine) have been studied in human embryos 4-8 weeks of age. Ultrastructure of cells in the extra- and intraorganic mesenchyme is described; to the latter belongs the leading role in organization the pathways of the prevascular microcirculation. The primary microvessels are formed as a result of canalization of the intercellular clefts, lining with mesenchymal cells, that gradually transfer into primordial endotheliocytes. Basing on ultrastructural analysis, certain stages of differentiation of protocapillary endotheliocytes have been defined and described in different organs. The change of the prevascular microcirculation into the intraorganic protocapillary bed (the primary blood bed) is an essential and necessary stage of the organogenesis.     

Lanthanum-induced damage to microvilli in cells of the posterior epithelium of the cornea and its trigger mechanism

Destructions in filament-membranous connections of microvilli of cells of the rabbit corneal posterior epithelium have been investigated after the effect of an ionized form of lanthanum. Rare-earth ions are used as a specific antagonist and as a substituent for calcium on the surface of biopolymeres. Twelve corneas from 6 rabbits of Shinshilla strain at the age of 2 months are used. Lanthanum ions are stated to have selective connections with the luminal part of the plasmolemma and with the membrane of the microvilli in the cells of the corneal posterior epithelium. The changes in the microvilli are accompanied with destruction of the filament-membranous connections producing protrusions and vesiculation of their plasmolemma, disaggregation of microfilaments adjoining the luminal part of the cellular plasmolemma. A suggestion is made on an impostant role of calcium and C++-binding biopolymeres in the mechanism regulating the filament-membranous connections.     

Effect of some negative stains on the calcium transport of sarcoplasmic reticulum

Summary Effect of some negative stains used in electron microscopy on calcium-transporting membranes of the fragmented sarcoplasmic reticulum (FSR) and interaction between stains and calcium have been studied.Calcium transport as well as ATP-ase activity of FSR are affected by stains investigated at concentrations lower than those used in electron microscopy. Degree of alteration varies from stain to stain. Phosphotungstic acid is the most effective inhibitor.Calcium loaded vesicles are depleted during resuspension in various staining solutions, in concentration routinely used for electron microscopy, according to the calcium affinity of the stain. Also in this respect phosphotungstic acid is the most effective.     

Localization of calcium in the secretory cells of the mammary glands in response to oxytocin

Distribution of Ca2+ ions, precipitated by means of pyroantimonate potassium, has been investigated electron microscopically in secretory cells of the mammary gland of lactating white mice. In the glandular cells, that are at the state of inhibition of secretory activity, the cytochemical reaction product is localized on the internal side of the basal, lateral and apical parts of the plasmolemma, in mitochondrial matrix, in cisterns and in the Golgi complex vesicles, in the nuclear areas, occupied by euchromatin. Oxytocin effect produces a certain complex of ultrastructural changes in the cell accompanied by redistribution of Ca2+ ions. Amount of precipitate in mitochondria decreases. It is revealed in the lumen of dilated canals of the granular endoplasmic reticulum, in the zone of decondensated nuclear chromatin, in the Golgi complex vesicles. The vesicles become larger and fuse with each other. The changes mentioned demonstrate increased synthetic and transport processes, occurring in the glandular epithelium of the mammary gland after oxytocin effect.     

Intranuclear inclusions in the cells of different tissues of the aging rat

Ultrastructure of neuronal and glial nuclei has been studied in various parts of the CNS, in parenchymatous cells of internal organs, in endotheliocytes and pericytes of their blood capillaries in intact rats--mature (6-8-month-old) and old (26-28-month-old), as well as at certain experimental influences. In all the cellular populations studied (most often in neurons), various in their structure, intranuclear inclusions (INI) have been revealed, that are considered as five main types. The number of INI increases sharply at ageing, that is especially noticeable under experimental conditions. Some INI are situated in morphologically preserved, actively working cells, being normal components of the nucleus, others--reflect profound rearrangements of nuclear proteins, disturbances in lipid metabolism up to irreversible destructive processes in the nucleus.     

Damage and regeneration of the endothelium of the aorta in experimental hypercholesterolemia

In dynamics of the experimental hypercholesterolemia in rabbits, peculiarities of endothelial regeneration have been studied. Comparison of proliferative activity level in endotheliocytes with structural-functional state of the endothelial monolayer at atherogenesis makes it possible to consider, that the lesion of the endothelium cannot be regarded as an initiating factor for formation of atherosclerotic lesions. Formation of the lesions in the internal lining of the arteries is preceded by certain disorders in permeability of the endothelial barrier at increasing concentration of cholesterin in blood plasma, accompanying with a sharp activation of the cell proliferative activity. When lipid plates and atherosclerotic plaques are already formed, the processes of the endothelial damage and regeneration occur in parallel. The regeneration is ensured with an intensive proliferation and growth of endotheliocytes onto deendotheliolized areas of the damaged intima.     

Ultrastructure of tissue basophils and capillaries during different periods of pre- and postnatal development of the dermis in the rat

Dynamics of ultrastructure of mast cells (MC) and that of the capillaries of the derma have been studied by means of electron morphometry methods in rats during pre- and postnatal ontogenesis. The dynamics of the Golgi complex volume, that of the mitochondria and specific granules have been calculated in the total volume of the MC membrane organelles. Certain new data have been obtained on the process of the MC specific granules formation in the derma from progranules up to the stage of a mature granule. The process mentioned is most intensive during the first weeks of the postnatal ontogenesis. At the age of two weeks, signs of an active exocytosis of the granules are noted. Judging by certain morphological signs, development of transendothelial transport of substances in capillaries takes place in parallel with formation of the specific granules and corresponds to the beginning of exocytosis of substances in the MC granules. The correlative analysis proves that formation of the MC specific granules is connected with the number of microvesicles in cytoplasm of endotheliocytes.     

Cytochemical identification of the leukocytes of torpedoes (Torpedo marmorata Risso and Torpedo ocellata Rafinisque)

The authors subjected peripheral blood smears of Torpedoes to cytochemical analysis of lipids, protein, neutral and acid polysaccahrides and of some enzymatic activities, i.e. adenosine triphosphatase (ATP-ase), acid and alkaline phosphatase, aliesterase and peroxidase. It was found that neutrophilic granulocytes are intensely PAS and aliesterase positive and weakly ATP-ase positive. Eosinophilic granulocytes show the presence of neutral polysaccharides in the matrix (which is PAS positive) and strong ATP-ase and acid phosphatase activities in the granules. Lymphocytes sometimes contain weakly PAS and aliesterase positive granules. Monocytes show some small PAS positive granules and weak acid phosphatase and aliesterase activities. Thrombocytes contain some peripheral granules which are PAS positive and slightly ATP-ase positive. There are no transitional forms between the various cellular types. The results confirm the classification of leukocytes of Torpedoes into neutrophilic granulocytes, eosinophilic granulocytes, lymphocytes, monocytes and thrombocytes and contribute some informations about the histoenzymatic content of Elasmobranch leukocytes.     

Muscle fibre composition of the eye muscles of the carp (Cyprinus carpio L.) defined on the base of histochemical observations

A histochemical study has been carried out on the eye muscles of the carp. On the base of the ATP-ase and SDH activity and with regard to the localization and diameter of muscle fibres six types of muscle fibres situated in the defined zones can be distinguished. The type 1 and 2 fibres display a moderately high ATP-ase activity at pH 9.4 and rather low activity after alkaline and acid preincubation. Type 1 shows a high SDH activity in contrast to type 2 with a low SDH activity. The other four types of fibres have the high ATP-ase activity at pH 9.4. Type 3 contains fibres with a moderately high ATP-ase activity after alkaline preincubation with a rather low activity after acid preincubation and with a low SDH activity. The fibres of type 4 characterized by the high ATP-ase activity after alkaline and acid preincubation and by the high SDH activity. The fibres of type 5 display high ATP-ase activity after alkaline and acid preincubation and the low SDH activity. They are situated in the white and intermediate fibre zones. The fibres of type 6 are comparable to the fibres of type 5, however they differ diameter and localization, i.e. they are situated in small diameter fibre zone. Using the electron microscope four types of fibres (A, B, C, and D) are found. They vary in the localization of T system, the organization of Z-line and in M-line appearance. In the type B of muscle fibres two different localizations of T system have been discerned.