The medium conditioned by dense, self-synchronized hepatocyte cultures was centrifuged at 150,000 g to obtain two fractions. The light fraction (supernatant fluid) contained ganglioside monomers and ...micelles, and the heavy fraction (pellet) contained gangliosides in the vesicles shed from the cell membrane. In the test populations of hepatocytes, the rhythm of protein synthesis was used as an indicator of cell synchronization resulting from their cooperative activity. Low-density hepatocyte cultures with asynchronous fluctuations of protein synthesis proved to be synchronized by both the initial conditioned medium and its vesicular fraction. Our previous studies have shown that this occurs under the effect of GM1 monosialoganglioside, which is released from cultured cells and accumulates in the conditioned medium. Liposomes consisting of GM1 and phosphatidylcholine from egg yolk (1:19 mol%), compared to free exogenous GM1, synchronized the rhythm of protein synthesis more effectively: synchronization was observed at a GM1 concentration in liposome suspension of only 0.0003 microM, compared to 0.06 microM and higher in the case of free GM1. Thus, GM1 as a component of membranes and monolayer lipid structures proved to be much more effective than free GM1 in promoting hepatocyte cooperation with respect to the rhythm of protein synthesis.
Previously we demonstrated synchronized oscillations of protein synthesis rate in the hepatocyte cultures upon accumulation of monosialognaglioside GM1 in the medium or after introduction of ...exogenous GM1 to the medium. The synchronized oscillations of the protein synthesis rate in dense hepatocyte cultures were blocked 30 min after their treatment with 10-20 microM BAPTA-AM--a chelating agent of cytoplasmic calcium. Enzyme immunoassay for GM1 demonstrated similar amounts of GM1 in the medium conditioned for 3 h by dense hepatocyte cultures pretreated with 20 micronsM BAPTA-AM for 1 h and in the medium of normal dense cultures--0.0060 +/- 0.0005 and 0.0055 +/- 0.0005 pmol/1000 cells, respectively. The content of GM1 was also similar in the normal and BAPTA-AM-pretreated hepatocytes--0.158 +/- 0.013 and 0.183 +/- 0.014 pmol/1000 cells, respectively. The synchronized rhythm of protein synthesis has been confirmed in the diluted cultures in the medium conditioned by the normal dense cultures. However, the medium conditioned by the dense cultures pretreated with BAPTA-AM induces no synchronization of the diluted cultures. Since GM1 concentration was normal in this medium, we propose the effect of physicochemical form of the gangliosides accumulated in the medium on their ability to synchronize the rhythm of protein synthesis.
Study of PEEP effects on breathing biomechanics in patients with pneumonia.
In 37 patients with pneumonia breathing biomechanics was studied using Masterlab (Jaeger). PEEP (3-10 cm H2O) was employed ...during 20 min.
Sputum expectoration, expiration and inspiration were improved, lung hyperventilation observed in pneumonia reduced after PEEP.
There is early expiration obstruction of the airways in pneumonia. PEEP removes this obstruction through control of lung hyperinflation. Thus, PEEP can be applied in the treatment of pneumonia.
The influence of PEEP breathing has been studied in 43 patients with exacerbation of bronchial asthma (BA) during 20 min in resistance of 5, 7 or 9 sm. Sputum expectoration and inspiration were found ...improved after PEEP breathing. Moreover, in some patients mild BA attacks relieved. Lung hyperinflation, bronchial obstruction reduced. A positive effect was observed in moderate asthma in PEEP breathing of 7 and 9 sm more frequently. This, PEEP breathing can be applied in the treatment of BA.
The effects of the antitumor drug tiazofurin on development of sea urchins Sphaerechinus granularis, Paracentrotus lividus, Strongylocentrotus intermedius, and Arbacia lixula were studied. When ...0.01-200 microM tiazofurin (TAF) was introduced in the incubation medium (artificial sea water) just after fertilization or at the midblastula stage, the development proceeded quite normally until the beginning of gastrulation. But later TAF blocked gastrulation and induced formation of mobile ball-shaped larvae with normal pigment cells but devoid of the nervous system, skeletal spicules and digestive tract. The threshold TAF concentrations varied from 0.05 microM (S. granularis) to 2-5 microM (all other species). When TAF was introduced during gastrulation and just after gastrulation, the larvae had defective nervous system and skeleton and suppressed expression of gangliosides. The nonhydrolyzable analog of GTP, GTP-gamma-S (5-20 microM), introduced in artificial sea water no later than at the midblastula stage prevented all above mentioned developmental defects.
Radiation studies are prominent in the diagnosis of extrapulmonary tuberculosis. X-ray study preserves its basic value. Its-based concepts of the pathology of osteoarticular, urogenital, ...lymphabdominal tuberculosis largely allow for analyzing the images obtained by new medical visualization techniques, such as X-ray tomography, computed tomography, magnetic resonance imaging, ultrasonography, and radionuclide studies. Each method has its merits and demerits and is used by a certain algorithm at different sites of extrapulmonary tuberculosis.
Indolylalkylamines (5-HT, 5-chlorotryptamine, 5-ethyltryptamine) suppress or block the progesterone-induced oocyte maturation in Bufo viridis and Xenopus laevis and disturb cytoskeletal ...rearrangements associated with oocytes involved, together with the other transmitter systems, in modulation of progesterone effect.
Zu, Cu, Cd, Pb and Hg salts blocked the cleavage divisions in the sea urchin embryos and, in lesser concentrations, affected gastrulation and induced postgastrulation defects. The early embryo- and ...cytotoxic effects of Zn salts appear to be based on the inhibition of protein synthesis. Unithiol exerted a protective effect. All salts under study inhibited protein synthesis in the Ehrlich's ascite carcinoma and ascite hepatoma 22a cells; unithiol and other suldhydryl compounds exerted in this case a good protective effect against Cd salts only.
It has been shown that cytotoxic action of neuropharmacological drugs (transmitter antagonists) on early urchin embryos is reduced or abolished by cyclic nucleotides and sodium fluoride. Such a ...protective action differs in cAMP and dibutyryl analogs of cyclic nucleotides, depending on the chemical structure of an embryotoxic substance. It is suggested that, endogenous intracellular "prenervous" transmitters and cyclic nucleotides are interrelated in the regulation of cell division in urchin embryos.
