Photosensitizers as Model Systems to Study Reactive Oxygen Effects in Biological Preparations

Cerebral ischemia resulting from a disruption of blood flow to the brain initiates a cascade of events that causes neuron death and leads to neurologic dysfunction. Reactive oxygen species are thought, at least in part, to mediate this disease process. The authors recently cloned and characterized an antioxidant protein, SAG (sensitive to apoptosis gene), that is redox inducible and protects cells from apoptosis induced by redox agents in a number of in vitro cell model systems. This study reports a neuroprotective role of SAG in ischemia/reperfusion-induced brain injury in an in vivo mouse model. SAG was expressed at a low level in brain tissue and was inducible after middle cerebral artery occlusion with peak expression at 6 to 12 hours. At the cellular level, SAG was mainly expressed in the cytoplasm of neurons and astrocytes, revealed by double immunofluorescence. An injection of recombinant adenoviral vector carrying human SAG into mouse brain produced an overexpression of SAG protein in the injected areas. Transduction of AdCMVSAG (wild-type), but not AdCMVmSAG (mutant), nor the AdCMVlacZ control, protected brain cells from ischemic brain injury, as evidenced by significant reduction of the infarct areas where SAG was highly expressed. The result suggests a rather specific protective role of SAG in the current in vivo model. Mechanistically, SAG overexpression decreased reactive oxygen species production and reduced the number of apoptotic cells in the ischemic areas. Thus, antioxidant SAG appears to protect against reactive oxygen species–induced brain damage in mice. Identification of SAG as a neuroprotective molecule could lead to potential stroke therapies.

Download Full-text

Effect of bromfenac on free radical oxidation in model systems

Kazan medical journal ◽

10.17816/kmj2019-636 ◽

2019 ◽

Vol 100 (4) ◽

pp. 636-641 ◽

Cited By ~ 1

Author(s):

E F Galimova ◽

Z G Khaibullina ◽

D A Enikeev ◽

Yu L Bortsova ◽

K S Mochalov ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Lipid Peroxidation ◽

Antioxidant Activity ◽

Free Radical ◽

Reactive Oxygen ◽

Free Radical Oxidation ◽

Model Systems ◽

Oxygen Species ◽

Radical Oxidation ◽

Anti Inflammatory

Aim. The study of free radical oxidation processes in an experiment on model systems using the anti-inflammatory drug bromfenac (nakwan) widely used in ophthalmology for the treatment of infectious and inflammatory diseases of the anterior chamber of the eye. Methods. The antioxidant capacity of the drug was evaluated by chemiluminescence registration and analysis of model systems that generate reactive oxygen species and reproduce lipid peroxidation processes using the chemiluminomer CL-003. The following parameters of spontaneous and induced chemiluminescence were determined: light sum and maximum luminescence amplitude, duration of latent period, amplitude of fast and slow flash. Results. When tested in vitro in two different model systems, a high antioxidant activity of the studied drug was established, up to complete suppression of chemiluminescence when 90 μg of bromfenac was added to the incubation medium, which characterizes the inhibition of the generation of reactive oxygen species. A significant increase in total antioxidant activity with bromfenac was also demonstrated, which is reflected by the integral parameter of chemiluminescence — light sum which decreased with the introduction of 10 μg of the drug by 1.2 times, and with 90 μg by 1.5 times. A comparative analysis of the antioxidant properties of various nonsteroidal anti-inflammatory drugs used in ophthalmic practice demonstrated a more pronounced efficacy of bromfenac compared to ketorolac, the use of which was not accompanied by statistically significant changes in chemiluminescence. A very important mechanism of the positive effect of bromfenac is the direct dependence of the action on its quantity in the reaction medium, which opens up prospects for the controlled correction of free radical phenomena and the excessive activation of lipid peroxidation in the imbalance of the pro- and antioxidant processes in biological systems. Conclusion. It is suggested that the protective effects of the drug in various infectious-inflammatory lesions of the eye can be determined, along with previously known properties, its antioxidant activity, restriction of increased production of reactive oxygen species and oxidative stress phenomena.

Download Full-text

Copper Oxide Nanoparticles Cause a Dose-Dependent Toxicity via Inducing Reactive Oxygen Species in Drosophila

Nanomaterials ◽

10.3390/nano8100824 ◽

2018 ◽

Vol 8 (10) ◽

pp. 824 ◽

Cited By ~ 14

Author(s):

Eugene Baeg ◽

Kanidta Sooklert ◽

Amornpun Sereemaspun

Keyword(s):

Reactive Oxygen Species ◽

Copper Oxide ◽

Reactive Oxygen ◽

Copper Oxide Nanoparticles ◽

The Body ◽

Model Systems ◽

In Vivo Model ◽

Oxide Nanoparticles ◽

Oxygen Species ◽

Dose Dependent

Copper oxide nanoparticles (CuONPs) have attracted considerable attention, because of their biocide potential and capability for optical imaging, however CuONPs were shown to be highly toxic in various experimental model systems. In this study, mechanism underlying CuONP-induced toxicity was investigated using Drosophila as an in vivo model. Upon oral route of administration, CuONPs accumulated in the body, and caused a dose-dependent decrease in egg-to-adult survivorship and a delay in development. In particular, transmission electron microscopy analysis revealed CuONPs were detected inside the intestinal epithelial cells and lumen. A drastic increase in apoptosis and reactive oxygen species was also observed in the gut exposed to CuONPs. Importantly, we found that inhibition of the transcription factor Nrf2 further enhances the toxicity caused by CuONPs. These observations suggest that CuONPs disrupt the gut homeostasis and that oxidative stress serves as one of the primary causes of CuONP-induced toxicity in Drosophila.

Download Full-text

Effects of Hyperoxia on Lung Utrastructure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067121 ◽

1970 ◽

Vol 28 ◽

pp. 26-27

Author(s):

Gladys Harrison

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Light Microscopy ◽

Oxygen Effects ◽

Age Dependent ◽

The Central Nervous System ◽

The Subject ◽

Space Age ◽

Alveolar Septa ◽

Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

Download Full-text

Nuclear coiled bodies and the nucleolus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100167834 ◽

1994 ◽

Vol 52 ◽

pp. 20-21

Author(s):

K. Brasch ◽

J. Williams ◽

D. Gallo ◽

T. Lee ◽

R. L. Ochs

Keyword(s):

Mouse Liver ◽

Nuclear Body ◽

Nuclear Bodies ◽

Model Systems ◽

Coiled Body ◽

Rrna Processing ◽

Malignant Cells ◽

Sm Proteins ◽

Coiled Bodies ◽

Unique Protein

Though first described in 1903 by Ramon-y-Cajal as silver-staining “accessory bodies” to nucleoli, nuclear bodies were subsequently rediscovered by electron microscopy about 30 years ago. Nuclear bodies are ubiquitous, but seem most abundant in hyperactive and malignant cells. The best studied type of nuclear body is the coiled body (CB), so termed due to characteristic morphology and content of a unique protein, p80-coilin (Fig.1). While no specific functions have as yet been assigned to CBs, they contain spliceosome snRNAs and proteins, and also the nucleolar protein fibrillarin. In addition, there is mounting evidence that CBs arise from or are generated near the nucleolus and then migrate into the nucleoplasm. This suggests that as yet undefined links may exist, between nucleolar pre-rRNA processing events and the spliceosome-associated Sm proteins in CBs.We are examining CB and nucleolar changes in three diverse model systems: (1) estrogen stimulated chick liver, (2) normal and neoplastic cells, and (3) polyploid mouse liver.

Download Full-text

Microtubule Dynamics and Organelle Transport in Reticulomyxa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158510 ◽

1990 ◽

Vol 48 (3) ◽

pp. 194-195

Author(s):

Yih-Tai Chen ◽

Ursula Euteneuer ◽

Ken B. Johnson ◽

Michael P. Koonce ◽

Manfred Schliwa

Keyword(s):

Plasma Membrane ◽

Light Microscopy ◽

Cytoplasmic Dynein ◽

Living Cells ◽

Microtubule Dynamics ◽

Model Systems ◽

Organelle Transport ◽

Biochemical Characteristics ◽

Dependent Transport

The application of video techniques to light microscopy and the development of motility assays in reactivated or reconstituted model systems rapidly advanced our understanding of the mechanism of organelle transport and microtubule dynamics in living cells. Two microtubule-based motors have been identified that are good candidates for motors that drive organelle transport: kinesin, a plus end-directed motor, and cytoplasmic dynein, which is minus end-directed. However, the evidence that they do in fact function as organelle motors is still indirect.We are studying microtubule-dependent transport and dynamics in the giant amoeba, Reticulomyxa. This cell extends filamentous strands backed by an extensive array of microtubules along which organelles move bidirectionally at up to 20 μm/sec (Fig. 1). Following removal of the plasma membrane with a mild detergent, organelle transport can be reactivated by the addition of ATP (1). The physiological, pharmacological and biochemical characteristics show the motor to be a cytoplasmic form of dynein (2).

Download Full-text

3-Dimensional immunolabeling and in situ hybridization detection using fluorescence photooxidation and intermediate-voltage Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168554 ◽

1994 ◽

Vol 52 ◽

pp. 164-165

Author(s):

Thomas J. Deerinck ◽

Maryann E. Martone ◽

Varda Lev-Ram ◽

David P. L. Green ◽

Roger Y. Tsien ◽

...

Keyword(s):

Laser Scanning ◽

Reactive Oxygen ◽

Confocal Laser Scanning Microscope ◽

Fluorescent Dye ◽

Confocal Laser ◽

3 Dimensional ◽

Voltage Electron ◽

Dimensional Distribution ◽

Electron Microscopes ◽

New Generation

The confocal laser scanning microscope has become a powerful tool in the study of the 3-dimensional distribution of proteins and specific nucleic acid sequences in cells and tissues. This is also proving to be true for a new generation of high contrast intermediate voltage electron microscopes (IVEM). Until recently, the number of labeling techniques that could be employed to allow examination of the same sample with both confocal and IVEM was rather limited. One method that can be used to take full advantage of these two technologies is fluorescence photooxidation. Specimens are labeled by a fluorescent dye and viewed with confocal microscopy followed by fluorescence photooxidation of diaminobenzidine (DAB). In this technique, a fluorescent dye is used to photooxidize DAB into an osmiophilic reaction product that can be subsequently visualized with the electron microscope. The precise reaction mechanism by which the photooxidation occurs is not known but evidence suggests that the radiationless transfer of energy from the excited-state dye molecule undergoing the phenomenon of intersystem crossing leads to the formation of reactive oxygen species such as singlet oxygen. It is this reactive oxygen that is likely crucial in the photooxidation of DAB.

Download Full-text

Microstructural observations of the “Wustite-Spinel” coexistence following quenching of cation-excess spinels, Ni2(1+x)Ti1-xO4

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178422 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1058-1059

Author(s):

Ian M. Anderson ◽

Arnulf Muan ◽

C. Barry Carter

Keyword(s):

Film Growth ◽

Spinel Phase ◽

Model Systems ◽

Ion Milling ◽

Coexistence Of Phases ◽

Nonequilibrium Conditions ◽

Diffraction Patterns ◽

Spinel Structures ◽

Highly Porous ◽

Standard Techniques

Oxide mixtures which feature a coexistence of phases with the wüstite and spinel structures are considered model systems for the study of solid-state reaction kinetics, phase boundaries, and thin-film growth, and such systems are especially suited to TEM studies. (In this paper, the terms “wüstite” and “spinel” will refer to phases of those structure types.) The study of wüstite-spinel coexistence has been limited mostly to systems near their equilibrium condition, where the assumptions of local thermodynamic equilibrium are valid. The cation-excess spinels of the type Ni2(1+x)Ti1-xO4, which reportedly exist only above 1375°C4, provide an excellent system for the study of wüstite-spinel coexistence under highly nonequilibrium conditions. The nature of these compounds has been debated in the literature. X-ray and neutron powder diffraction patterns have been used to advocate the existence of a single-phase, non- stoichiometric spinel. TEM studies of the microstructure have been used to suggest equilibrium coexistence of a stoichiometric spinel, Ni2TiO4, and a wüstite phase; this latter study has shown a coexistence of wüstite and spinel phases in specimens thought to have been composed of a single, non- stoichiometric spinel phase. The microstructure and nature of this phase coexistence is the focus of this study. Specimens were prepared by ball-milling a mixture of NiO and TiO2 powders with 10 wt.% TiO2. The mixture was fired in air at 1483°C for 5 days, and then quenched to room temperature. The aggregate thus produced was highly porous, and needed to be infiltrated prior to TEM sample preparation, which was performed using the standard techniques of lapping, dimpling, and ion milling.

Download Full-text