Effect of perfluorocarbon emulsions on rheological parameters of blood

The effect of a perfluorocarbon emulsion on the rheological parameters of blood in a living organism at the hematocrit twice lower than the norm was studied. It was shown that an increase in emulsion concentration leads to an increase in blood asymptotic viscosity and the aggregation of erythrocytes. It was concluded that only a small volume of the fluorocarbon phase of particles, as compared with the total amount of erythrocytes, can improve the blood fluidity upon disturbed circulation.     

Effect of perfluorocarbon emulsions on the protective properties of cardioplegic solutions

The influence of ischemia and conventional and emulsion cardioplegia on the dynamics of resting tension, Ca2+ concentration, the level of membrane potential and oxygen tension in the myocardium was studied. It was shown that emulsion cardioplegia prolonged the duration of anoxic protection due to the additional oxygen supply of tissues and the decrease in Ca2+ cytoplasm accumulation.     

Effect of the interfacial surfactant layer on oxygen transfer through the oil/water phase boundary in perfluorocarbon emulsions

The effect of interfacial surfactant molecules on oxygen transfer through oil/water phase boundary has been studied in FlurO(2) (TM) emulsions, i.e., perfluorocarbon (PFC) emulsions developed as oxygen carriers in cell culture. Measurements of oxygen permeability were made with a polarographic oxygen electrode in pure PFCs and in emulsions with various PFC volume fractions. Comparison of the experimental results with the theoretically derived values of relative oxygen permeability clearly indicates that the mass transfer resistance caused by the interfacial surfactant layer in PFC emulsions is insignificant. Therefore, oxygen dissolved in the enclosed PFC phase is readily available to cells growing in the aqueous media and FlurO(2) emulsions with very fine emulsion particles (< 0.2 mum) can be used to effectively enhance gas/liquid interfacial oxygen transfer in bioreactors. The inadequacy in describing mass transfer in heterogeneous systems, such as the PFC emulsions, by conventional concentration-based oxygen diffusion coefficients has also been discussed.     

Use of perfluorocarbon emulsions in cell culture.

Perfluorocarbon emulsions were applied to hybridoma cultures grown in tissue culture tubes and column bioreactors. The oxygen transfer enhancement effect of perfluorocarbon emulsions was clearly demonstrated by the higher cell densities obtained in emulsion-supplemented systems. In addition, perfluorocarbon emulsions were shown to provide better cell suspension in a low-shear environment. The study in column bioreactors also suggested a cell protective effect of the employed perfluorocarbon emulsions in reducing the damage to cells by gas bubbles.     

Generation of active forms of oxygen by human peripheral blood neutrophils and lymphocytes during adhesion to glass

Oxygen activation by neutrophils and human blood lymphocytes at adhesion to glass have been studied by luminol--dependent chemiluminescence. It has been established that the cell interaction with glass leads to the formation of O2-., O2', .OH and H2O2. Chemiluminescence kinetics and the excited--oxygen forms ratio at adhesion were different for neutrophils and lymphocytes. The desorption of cells resulted in a decrease of the chemiluminescent response to neutrophils and lymphocytes when they again adhered to glass and in practically complete inhibition of chemiluminescence induced by adding concanavalin A. It has been determined that at adhesion of neutrophils and lymphocytes to glass different mechanisms of oxygen activation take place.     

Effect of psoralens on Fenton-like reaction generating reactive oxygen species

Psoralens (psoralen, 5-methoxypsoralen, 8-methoxypsoralen, khellin, and visnagin) in 1 mM doses were shown to enhance the generation of reactive oxygen species, such as the hydroxyl radical (HO*), the superoxide anion radical (O2(-)), and singlet oxygen ((1)O(2)), from the system generating chemiluminescence (CL), as well as free radicals in the absence of light. The system that generated CL was made up of CoCl(2) and H(2)O(2). Incubation of psoralens in 0.2 mM doses with the generating system showed that only 8-methoxypsoralen and khellin have antioxidative effects. Antioxidative effects were also observed in the case of visnagin but in low concentration (0.05 mM). High doses of psoralens (1 mM) showed prooxidative effects. Measurements were done using a deoxyribose assay, the CL method, and spin-trapping with 5,5-dimethyl-1-pyrroline-N-oxide and 2,2,6,6-tetramethylpiperidine combined with electron spin resonance spectroscopy and spectrophotometry methods.     

Post-receptor formation of active forms of oxygen in nonphagocytic cells]

Generation of reactive oxygen species (ROS) in A431 cells, NIH3T3 fibroblasts expressing normal epidermal growth factor (EGF) receptor, L929 fibroblasts, and in mouse peritoneal macrophages (professionally phagocytic cells) upon the effect of different activators has been studied. It has been shown that ROS formation in A431 and NIH3T3 cells upon the effect of EGF is time- and dose-dependent process. A variety of stimuli were used to stimulate macrophage ROS production. However, the effect of only phorbol ester, opsonized zymozan, peptide fMLP, and platelet activating factor led to ROS generation, whereas tumor necrosis factor alpha, interferon gamma, and lipopolysaccharide did not stimulate macrophage oxidative burst. The literature data on ROS generation in a variety of cell types are presented. ROS formed in cells acted upon certain agents are considered as the molecules participating in intracellular signaling.     

Role of active forms of oxygen in inducing luminol-dependent chemiluminescence in macrophages

The luminol-dependent chemiluminescence of mouse peritoneal macrophages during phagocytosis of opsonized zymosan was studied by using specific active oxygen scavengers and metabolic inhibitors. Extracellular hydrogen peroxide and superoxide anion were shown to contribute immensely to the induction of the chemiluminescence. The role of the hydroxyl radical was rather insignificant, whereas singlet oxygen was not involved in this process. The interaction between luminol and peroxide was shown to be peroxidase-dependent. An inhibitory analysis revealed that the interaction between luminol, peroxide and superoxide anion obeyed a hybrid enzyme-free radical mechanism.     

Use of perfluorocarbon emulsions for administration of photosensitizing preparations into bone marrow stem cells

It has been shown that, upon incubation of mouse bone marrow stem cells (BMSC) in vitro with the nanoparticles of perfluorocarbon (PFC) emulsion stabilized by proxanol 268, these nanoparticles penetrate into cells and stay there for a long time (up to 20 days of observation). It has been found that, under in vitro conditions, mouse BMSC loaded with the nanoparticles of both the original emulsion and the emulsion preliminarily incubated with radachlorine do not differ from control stem cells in the rate of division, stretching on a plastic support, and the formation of a monolayer. It has been shown that the exposure to laser radiation of BMSC incubated with the nanoparticles of a PFC emulsion preliminarily incubated with radachlorine under in vitro conditions leads to the death of these cells due to the destruction of the cell membrane. The treatment with laser radiation of BMSC incubated with the nanoparticles of the starting PFC emulsion (without preliminarily incubation with radachlorine) causes no death of these cells. It has been shown in in vivo experiments that, when transplanted to the organism of a recipient mouse, BMSC of a donor mouse incubated with the nanoparticles of a PFC emulsion preliminarily incubated with radachlorine retain their functional activity, in particular the ability to migrate in the animal body. In this case, radachlorine contained in these stem cells retains its major function, to induce the death of stem cells by the action of laser radiation due to the destruction of the cell membrane. The observation period after the transplantation was 5-7 days.     

Moraxella species are primarily responsible for generating malodor in laundry

Many people in Japan often detect an unpleasant odor generated from laundry that is hung to dry indoors or when using their already-dried laundry. Such an odor is often described as a "wet-and-dirty-dustcloth-like malodor" or an "acidic or sweaty odor." In this study, we isolated the major microorganisms associated with such a malodor, the major component of which has been identified as 4-methyl-3-hexenoic acid (4M3H). The isolates were identified as Moraxella osloensis by morphological observation and biochemical and phylogenetic tree analyses. M. osloensis has the potential to generate 4M3H in laundry. The bacterium is known to cause opportunistic infections but has never been known to generate a malodor in clothes. We found that M. osloensis exists at a high frequency in various living environments, particularly in laundry in Japan. The bacterium showed a high tolerance to desiccation and UV light irradiation, providing one of the possible reasons why they survive in laundry during and even after drying.     

Functional heterogenicity of human blood neutrophils: generation of oxygen active species

Kinetics of neutrophil inactivation was investigated in vitro by Nitroblue tetrazolium (NBT) test in the process of their contact with the substrate. It has been shown that the previous thermostatation results in an exclusive inactivation of neutrophils with high reaction ability leading to their complete inactivation. Such an inactivation is a consequence of cell contacts with the substrate, whose chemical structure and physicochemical properties define the process regularities. The neutrophil inactivation is probably not a consequence of the contact itself but may follow the next scheme: stimulus (contact with substrate)--generation of reactive oxygen metabolites--inactivation. Two functional unequal classes of neutrophils were differentiated on the basis of different levels of their reactive oxygen metabolite generation, and on their ability to inactivation. In vitro cells of one of these classes actively generate reactive oxygen metabolites to be inactivated in consequence of interaction with the substrate, whereas cells of the other class produce reactive oxygen metabolites less actively and are nor inactivated. Evidently, in vivo cells of the are phagocytes and those of the latter fulfill other functions.     

Antioxidative properties and degradation of serum proteins by active oxygen forms (O2-., OCl-) generated by stimulated neutrophils

The ability of major serum proteins (albumin, immunoglobulin G) and free radical scavenger proteins (ceruloplasmin, superoxide dismutase, transferrin) to interact with O2-. and OCl- was studied. The interaction between serum proteins and OCl- was shown to be nonspecific and cause protein degradation. During SDS polyacrylamide gel electrophoresis ceruloplasmin and transferrin were degraded in the highest degree. Protein damage was also recorded by fluorescence changes. It is suggested that the damaging influence of active oxygen species secreted by stimulated neutrophils into the extracellular space can be abolished only by ceruloplasmin.     

The role of active forms of oxygen in platelet aggregation and deaggregation

The effect of hydrogen peroxide on ADP-induced platelet aggregation in the presence of active oxygen species scavengers was studied. It was shown that the superoxide radical and singlet oxygen, alongside with hydrogen peroxide, may play a role in platelet interactions.     

A unique vacuolar processing enzyme responsible for conversion of several proprotein precursors into the mature forms.

Proprotein precursors of vacuolar components are transported from the endoplasmic reticulum into vacuoles, where they are proteolytically processed into their mature forms. However, the processing mechanism in plant vacuoles is very obscure. Characterization of a purified processing enzyme is required to determine whether a single enzyme is responsible for processing many vacuolar proteins with a large variability of molecular structure. If this is true, how can it recognize the numerous varieties of processing sites? We have now purified a processing enzyme (Mr = 37,000) from castor bean seeds. Our results show that the purified enzyme can process 3 different proproteins isolated from either the endoplasmic reticulum or transport vesicles in cotyledon cells to produce the mature forms of these proteins which are found at different suborganellar locations in the vacuole: the 2S protein found in the soluble matrix, the 11S globulin found in the insoluble crystalloid and the 51 kDa protein associated with the membrane. Thus a single vacuolar processing enzyme is capable of converting several proprotein precursors into their respective mature forms.     

Application of perfluorocarbon emulsions for the administration of photosensitizing preparations into bone marrow stem cells

It has been shown that, upon incubation of mouse bone marrow stem cells (BMSC) in vitro with the nanoparticles of perfluorocarbon (PFC) emulsion stabilized by proxanol 268, these nanoparticles penetrate into cells and stay there for a long time (up to 20 days of observation). It has been found that, under in vitro conditions, mouse BMSC loaded with the nanoparticles of both the original emulsion and the emulsion preliminarily incubated with radachlorine do not differ from control stem cells in the rate of division, stretching on a plastic support, and the formation of a monolayer. It has been shown that the exposure to laser radiation of BMSC incubated with the nanoparticles of a PFC emulsion preliminarily incubated with radachlorine under in vitro conditions leads to the death of these cells due to the destruction of the cell membrane. The treatment with laser radiation of BMSC incubated with the nanoparticles of the starting PFC emulsion (without preliminarily incubation with radachlorine) causes no death of these cells. It has been shown in in vivo experiments that, when transplanted to the organism of a recipient mouse, BMSC of a donor mouse incubated with the nanoparticles of a PFC emulsion preliminarily incubated with radachlorine retain their functional activity, in particular the ability to migrate in the animal body. In this case, radachlorine contained in these stem cells retains its major function, to induce the death of stem cells by the action of laser radiation due to the destruction of the cell membrane. The observation period after the transplantation was 5–7 days.     

Characteristics of the production of active oxygen species from adherent and non-adherent neutrophils

Our objective was to evaluate the characteristics of the production of AOS from the neutrophils that had adhered to the endothelial cells, fibronectin or polystyrene, using the method of electron paramagnetic resonance (EPR) spin trapping. Neutrophils and endothelial cells were isolated from human venous blood and umbilical veins, respectively. AOS production from neutrophils was not elicited only by adhesion. The stimulation of adherent neutrophils with phorbol myristate acetate (PMA) induced the production of AOS. The production of AOS from adherent neutrophils to endothelial cells, but not to fibronectin or polystyrene, decreased with the interval time between the adhesion and the stimulation by PMA. The amount of AOS produced by the neutrophils adherent to fibronectin or polystyrene was maintained for one hour after stimulation with PMA, whereas that by suspended neutrophils gradually decreased with the time after stimulation. Results indicate that adherent and non-adherent neutrophils exhibit differing time course of AOS production.