[Comparative light microscopic, scanning-electron microscopic and electron microscopic studies of the effect of experimental interventions by surgical scalpel, electrocautery and CO2-laser beam in the oral cavity]. / A sebészi szikével, az elektrokauterrel és a CO2-lézersugárral kísérletesen a szájüregben létrehozott beavatkozások hatásának fénymikroszkópos, scanning-elektronmikroszkópos és elektronmikroszkópos összehasonlító vizsgálata.

Tissue effect interventions by means of surgical scalpel, elecrtokauter and CO2-laser ray in the mouth cavity of 20 white rats has been examined. According to their light microscopical examinations both the laser and the electrokauter caused thermal injuries taking place in typical zones while by the scalpel the cut surface in rendered ragged. The band-width of the thermoinjury caused by the kauter is a multiple of that caused by the laser. It has been proved by means of scanning electronmicroscopical examinations that interventions by means of laser result in sharp wound borders, the wounds cut by means of kauter are characterised by the presence of a great number of carbonized specks while by means of the scalpel a mechanical tear of the tissues is brought about. By means of electronmicroscopical examination the characteristics of the typical thermoinjured zones are described. It has been established that in the case of laser the injury of the ultra-structure extends to 400 microns while in case of electrokauter it reaches a width of 1500 microns. The excellent haemostatic effect brought about by the thermoeffect by means of the laser, in contrast to the broad thermoinjured zone caused by the kauter, is obtained at a very mild thermoinjury.

Effect of X-irradiation on adenylate cyclase activity and cyclic AMP content of primary human fibroblasts.

Ionizing radiation provokes an increase of the cAMP level in several organs and body fluids. After reviewing the relevant literature we present the results of our own experiments on primary human fibroblasts. X-irradiation at doses of 0.5 and 2.5 Gy in vitro evoked a rapid and reversible increase of adenylate cyclase enzyme activity. A significant increase in cAMP level of these cells was also observed. Adenylate cyclase was usually localized basolaterally on the surface of unirradiated cells, while irradiation resulted in a modification of distribution, i.e., the enzyme activity also appeared in apical localization.

Acceleration of the internalization of ligand-bound membrane DNA by thyroxine treatment in macrophages.

The localization of membrane DNA and the binding and internalization of DNase-colloidal gold complex were examined in mouse peritoneal macrophages in presence and absence of thyroxine (T4). Preexposure to the hormone for 5 to 10 min caused no change relative to the control but preexposures for 30, 60, and 90 min accounted for an increase in the ligand binding capacity, aggregation of the DNase-gold particles on the cell surface, and appearance thereof in coated pits, coated vesicles, smooth vesicles and, finally, inside lysosomes. After 30 min preexposure to T4, subsequent 10 min treatment with the DNase-gold complex was as effective as 1 h treatment had been without T4.

Localization of amino acid hormones (adrenalin, serotonin, histamine and a hormone precursor (5-hydroxytryptophane) in Ascidia cells.

All tritiated amino acid hormones added to the maintenance medium of Ascidia mentulosa entered the cells of the coat and gut, and all appeared in intranuclear localizations. The quantitative differences in incorporation did not indicate a specific affinity for any hormone tested.

Internalization and localization of membrane-associated DNA in the Tetrahymena.

The Tetrahymena does possess membrane-associated DNA, which binds the DNA-ase-gold complex. After binding, the DNA-DNA-ase-gold complex entered the cells mainly in vacuoles delimited by unilamellar membranes, less often in coated vesicles, which released the complex near to the nucleus, to judge from appearance of gold colloid particles along the nuclear membrane and, occasionally, above the nuclear pore or, infrequently, inside the nucleus itself.

Simultaneous electron microscopic detection of colloidal gold labeled ligand and adenylate cyclase. Influence of concanavalin-A on adenylate cyclase activity of fibroblasts.

Concanavalin-A-colloidal gold (Con-A-G) complex and adenylate cyclase activity were detected simultaneously in electron microscopic preparations of human fibroblast cultures, by a combined histochemical technique. The colloidal gold particles appeared as round bodies which could be readily differentiated from the amorphous product of the adenylate cyclase enzyme reaction. The combined technique makes possible the simultaneous visualization of the bound ligand (i.e. of its binding site), and of the enzyme activated by the ligand. Treatment of the cells with Con-A accounted for a considerable increase in intracellular adenylate cyclase activity. The activity increase was disproportionally greater than the amount of bound ligand, and it also appeared in localizations showing no indication of ligand binding. Treatment of the fibroblasts with Con-A was followed by internalization of the ligand and the enzyme inside at least seemingly segregated vesicles.

Detection of localization and internalization of membrane DNA in the Tetrahymena by the lactoferrin--colloidal gold technique.

It is known that lactoferrin binds to DNA. In the present study a lactoferrin-gold complex bound initially to the ciliary membrane, then appeared in coated pits and intracytoplasmic vesicles. On treatment for 1 h, the gold particles could be detected near to the nucleus. The lactoferrin-gold complex neither bound to the surface, nor appeared in the cytoplasm of those cells which had been exposed to DNAse for pretreatment.

Studies on internalization and intracellular localization of membrane DNA in mouse peritoneal macrophages, by means of lactoferrin-gold complex.

It is an experimental fact that lactoferrin binds to DNA. In the present study, a lactoferrin-gold complex was first bound by the cell surface, then became internalized (inside coated or smooth vesicles). Intracellularly the complex appeared in tube-like or vesicle-like structures, which approximated the nucleus, and some vesicles even showed indications of association with the external nuclear membrane. Neither membrane binding, nor internization of the lactoferrin-gold complex had taken place in cells pretreated with DNase.

Internalization and heterochromatic localization of 3H-di-iodothyrosine (T2) in the unicellular organism Tetrahymena and rat thymocytes.

Diiodotyrosine (T2) binds in Tetrahymena to ciliary membranes and enters the cell by endocytosis and also by other means (diffusion?). It can be found in the nucleus within, always in heterochromatic localization. The mitochondrial localization is also characteristic. In rat lymphocytes T2 is present in the cytoplasm independently from vesicles and it appears in the nucleus later than in Tetrahymena but invariably in heterochromatic localization. It can also be seen in the chromosomes of mitotic cells.

Electron microscopic localization and hormonal (diiodotyrosine) induction of adenylate cyclase in the Tetrahymena.

Normal Tetrahymena cells exhibited adenylate cyclase activity exclusively in association with pinocytotic vesicles, whereas those treated with diiodotyrosine (T2) for growth stimulation showed it in association with the cell membrane, and intracellularly inside many dense bodies. It appears that hormonally activable adenylate cyclase is an inherent component of the Tetrahymena.

Coated pits and coated vesicles in unicellulars (Tetrahymena, Crithidia) and in Hydra.

Coated pits and coated vesicles were observed in the ciliated unicellular Tetrahymena, in the flagellated unicellular Crithidia, and in Hydra. In the unicellulars the coated structures localized for the most part near to the origin of cilia or flagella, and many were present around the Golgi complex, whereas in Hydra they occurred in nonspecific random locations. Since the membrane receptors of the unicellulars serve originally as food receptors, the coated pits and vesicles are presumably involved in food selection, and represent as such the primitive form of the receptor-mediated ligand internalization mechanism operative in higher organisms.

Comparative study of the internalization and nuclear localization of amino acid type hormones in Tetrahymena and rat lymphocytes.

Tetrahymena pyriformis GL cells and rat thymic lymphocytes equally showed intranuclear incorporation of triiodothyronine, diiodotyrosine, histamine, serotonin, epinephrine and corticosterone--used as control--on exposure to labelled hormones. All hormones appeared in the nucleus in a predominantly heterochromatic localization. Lymphocytes, although smaller in size, incorporated more hormone than Tetrahymena. The intranuclear accumulation of corticosterone did not differ between Tetrahymena and thymocytes, and was high in both relative to total incorporation by the cell. Autoradiographically detected localizations did not notably vary with the type of cell or hormone.

Electron microscopic study of the overlapping effect of thyrotropin and gonadotropins on the Sertoli cells of chick embryo.

The ultrastructural features of the Sertoli cells of the embryonic chick testis have been studied following the administration of thyrotropin (TSH) and gonadotropins (FSH + LH), on the 8th or 15th day of embryonic life. The principal changes observed in the 15-day TSH-treated embryos were the increased quantities of Sertoli cell organelles, particularly the agranular endoplasmic reticulum, mitochondria and Golgi complex. Although the same changes were observed in the gonadotropins-treated embryos, it is worthwhile to mention that the Sertoli cells of 15-day TSH-treated embryos contain abundant granular endoplasmic reticulum more than that in the gonadotropin treated ones. The most striking ultrastructure feature, the occurrence of coated vesicles in Sertoli cells in all groups including control, however they appear much numerous in 15-day treated embryos. The findings of the present investigation support the hypothesis that TSH has an extrathyroidal role and demonstrate the functional responsiveness of 15-day chick embryo Sertoli cells to this hormone. The FSH-like activity of TSH agrees with our earlier hypothesis: namely that hormones of similar molecular structure may bind to the same binding sites as a consequence of receptor immaturity.

Overlapping effect of follicle stimulating hormone (FSH) and thyrotropin (TSH) on the ultrastructure of immature chicken testes.

In newly hatched chicken testes the gonadotropin receptors due to their immaturity are not specific but still structurally versatile and so they can bind both FSH and TSH which have a chemically related structure. The functional overlapping effect of FSH and TSH on the ultrastructure of Sertoli and Leydig cells of immature chicken testes was investigated. The activity of Sertoli cells was increased by FSH treatment and this increase correlated well with the amount of SER and RER in cells and with their increased surface activity. The vacuolization and degeneration observed at the apical part of the cells may refer to the formation of testicular tubules. After TSH treatment cell activity increased and in addition a considerable increase in RER and lipid droplets was observed. Fenestrated cisternae were often found in the Sertoli cells of the treated animals. In the Leydig cells, both hormones increased lysosomal activity and the number of lipid droplets. After FSH treatment the amount of SER increased while after TSH treatment the Golgi activity.

Binding and internalization of 3H-epinephrine in Tetrahymena.

Exposure of Tetrahymena to exogenous epinephrine is followed by appearance of the hormone in the cell membrane, intracytoplasmic vacuoles and nucleus. The intra-nuclear localization is always heterochromatic. Only a minor proportion of the applied epinephrine dose gains access to the nucleus, while the bulk of it attaches to the membrane.