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PubMed1996

Assessment of aspects of the toxicity of Clostridium perfringens epsilon-toxin using the MDCK cell line.

1. The epithelial Madin Darby Canine Kidney (MDCK) cell line was used to study the toxicity of epsilon-toxin from Clostridium perfringens. The epithelial MDCK cell line is known to be sensitive to epsilon-toxin of Clostridium perfrigens and to investigate its mechanism of action, the neutral red assay has been used to dermine the viability of cultures of this cell line. 2. Comparison of the LC50s obtained at 34 degrees C and 0 degree C showed that the lethality of epsilon-toxin was reduced by 18-fold at the lower temperature. The effect of temperature on epsilon-toxin lethality is unlikely to be due to reductions in membrane fluidity for the addition of Ca2+ or Mg2+ (2 mM) to buffer containing toxin was without effect. Varying the pH of the toxin-containing buffer from 6.9 to 8.7 did not increase the lethality of the toxin, though the most acidic pH used (5.8) was found to potentiate its action on MDCK cells. 3. The effect of inhibiting endocytosis on the lethality of epsilon-toxin was also investigated by incubating cultures of MDCK cells with and without sodium azide over a range of concentrations of toxin. The co-administration of sodium azide did not reduce the toxicity of epsilon-toxin, suggesting that energy-dependent uptake processes such as endocytosis were unlikely to be involved in its mechanism of action. The results are, however, consistent with known receptor-based mechanisms of uptake and with other mechanisms of internalisation across the plasma membrane. epsilon-toxin thus interacts with cell surfaces by a temperature sensitive mechanism potentiated by low pH.

Animals↗

PubMed1981

A scanning electron microscopic study of the two-step effect of cytochalasin B on Ehrlich ascites tumor cells.

The effect of cytochalasin B (CB) on the surface structure of Ehrlich ascites tumor cells was investigated using the scanning electron microscope. The effect occurs in two steps: formation of zeiotic knobs on the cell surface and subsequent grouping of the knobs at one pole of the cell. The early step of zeiotic knob formation occurs at low concentrations of CB (0.5-1 microgram/ml) at 37 degrees C and at high concentrations of the drug (5-10 microgram/ml) at low temperature but within 1 min at 37 degrees C. This step is only partially inhibited by 5 x 10(-3) M sodium azide. The subsequent grouping of zeiotic knobs lasts for more than 2 min at 37 degrees C and occurs only in the case of high concentrations of CB. It is inhibited by sodium azide and is often associated with grouping of the microvilli, which are then lost from all of the cell surface except the area of knob-grouping.

Animals↗

PubMed1991

Increased phagocytic activity of polymorphonuclear leukocytes of chronic granulomatous disease as determined with flow cytometric assay.

Using flow cytometry, we compared the phagocytic activity of polymorphonuclear leukocytes (PMNs) from healthy donors with that of PMNs from 10 patients with chronic granulomatous disease (CGD), eight carriers of X-linked CGD, and one patient with myeloperoxidase deficiency. Ingestion of fluorescent bacteria by CGD and myeloperoxidase-deficient PMNs was significantly increased, that is, about 1.5 times that of normal controls. In CGD carriers, two PMN populations were found: one population consisted of PMNs with enhanced phagocytosis, and the other consisted of PMNs with normal phagocytic activity. With a two-dimensional analysis, we also demonstrated in CGD carriers that phagocytosis of the PMNs that failed to generate hydrogen peroxide was significantly elevated, as was phagocytosis of PMNs in patients with CGD, while on the other hand, the PMNs that normally produced hydrogen peroxide exhibited a normal phagocytic activity. When sodium azide, an inhibitor of myeloperoxidase and catalase, was added to control and carrier PMNs, phagocytic activity was significantly increased, p less than 0.01 in both, but not to the level seen with CGD PMNs. Phagocytosis of CGD and myeloperoxidase-deficient PMNs, however, remained unchanged by the azide treatment. On the basis of above findings, we speculate that phagocytosis of CGD PMNs is increased because the H2O2-myeloperoxidase-halide system, which may modulate phagocytic activity of PMNs, fails to operate.

Adolescent↗

PubMed1989

Role of differential drug uptake, efflux, and binding of etoposide in sensitive and resistant human tumor cell lines: implications for the mechanisms of drug resistance.

In order to study the mechanism of etoposide (VP-16) resistance in human tumor cells and to assess the role of P-170 glycoprotein in VP-16 accumulation, we have examined the uptake and efflux of VP-16 in both sensitive and multidrug-resistant MCF-7 human breast and HL60 human promyelocytic leukemia cells. The drug-resistant cells, MCF-7/ADR and HL60/ADR, were selected for resistance to adriamycin and were 200- to 250-fold resistant to VP-16. Whereas MCF-7/ADR cells overexpress the P-170 glycoprotein and show the multidrug-resistant phenotype, HL60/ADR cells do not overexpress the P-170 glycoprotein. Although there was a 2-fold decrease in accumulation of VP-16 in MCF-7/ADR cells, this decrease did not correlate with a 250-fold resistance to the drug. VP-16 efflux was rapid and almost complete from MCF-7 cell lines and it was decreased at 4 degrees. Further, there was a significant increase in VP-16 accumulation in the MCF-7/ADR cells in the presence of glucose-free medium supplemented with sodium azide. However, no change in the pattern of VP-16 efflux was observed. Under these conditions, addition of glucose caused release of VP-16 from MCF-7/ADR cells, suggesting energy-dependent modifications in the drug binding. Coincubation of vincristine with VP-16 also increased the drug accumulation and decreased the rate of efflux of VP-16 in both sensitive and resistant MCF-7 cells, suggesting that vincristine and VP-16 may compete for similar binding and efflux mechanisms in these cell lines. In contrast, daunorubicin increased VP-16 accumulation only in the sensitive MCF-7 cell line, whereas the efflux rate of VP-16 was not significantly changed in either cell line. HL60 sensitive cells accumulated 4- to 5-fold more VP-16 than the resistant subline. Both sensitive and resistant cells showed an important noneffluxable pool of the drug, 3-fold larger for sensitive cells (79 +/- 12 versus 25 +/- 2 pmol of VP-16/mg of protein, for sensitive and resistant cells, respectively). The efflux of VP-16 was temperature dependent only in sensitive cells. VP-16 accumulation in HL60/ADR cells was increased in glucose-free medium supplemented with sodium azide; however, the noneffluxable pool of VP-16 was not significantly changed. In contrast, although these conditions had no effect on the drug accumulation in the parental line, they caused a decrease in the noneffluxable pool of VP-16, suggesting an energy-dependent binding and retention of VP-16.(ABSTRACT TRUNCATED AT 400 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1989

[Centrosome behavior in the exposure of tissue culture cells to energy metabolism inhibitors].

The organization of the centrosome in PK cells has been analysed according to several parameters: the presence of primary cilium, the number of pericentriolar satellites, the presence of striated rootlets, the distance between two centrioles and their orientation as regards the substrate plane. 2,4-Dinitrophenol (DNP), DNP with deoxyglucose (DOG), sodium azide cause the increase of frequency of occurrence of primary cilia and the growth of mean number of satellites per active centriole. The distribution of active and inactive centrioles in control cells is described by a histogram corresponding to a histogram of accidental distribution. Under the action of DNP or DNP with DOG, but not of sodium azide a part of active centrioles settled down perpendicularly to the substrate plane increases. The orientation of inactive centrioles under all the treatments used doesn't practically change.

2,4-Dinitrophenol↗

PubMed1988

Modulation of human polymorphonuclear leukocyte function by the flavonoid silybin.

The effect in vitro of the naturally occurring flavonoid silybin on human polymorphonuclear leukocyte (PMN) functions has been studied. Preincubation of PMNs for 10 min at 37 degrees C with silybin inhibited, in a dose-dependent way, the luminol-enhanced chemiluminescence (CL) generated by stimulated cells without affecting the non-enhanced CL or superoxide anion production evaluated by the cytochrome C reduction assay. No significant effect of silybin on PMN phagocytic or chemotactic activities were found. Silybin did not absorb light at the wavelength of luminol-enhanced CL and was not toxic to PMNs at the concentrations used. Catalase, a scavenger of H2O2, inhibited luminol-enhanced CL to a similar degree as silybin; moreover, when incubated together with PMNs, silybin and catalase did not produce an additive inhibition of CL. On the contrary, the simultaneous addition of silybin and sodium azide, an inhibitor of myeloperoxidase, further increased inhibition over that seen with azide alone. These results suggest that inhibition of H2O2 may be the mechanism by which silybin inhibits the luminol-enhanced CL generated by stimulated PMNs. Such results indicate a possible anti-inflammatory activity for silybin even if their clinical relevance remains to be elucidated.

Azides↗

PubMed1988

Characterization of trimetrexate transport in human lymphoblastoid cells and development of impaired influx as a mechanism of resistance to lipophilic antifolates.

The purpose of this study was to characterize the transport properties of trimetrexate in WI-L2 human lymphoblastoid cells and determine the mode of resistance that had developed in a subline, WI-L2/TMQ, that was grown in increasing concentrations of trimetrexate. WI-L2/TMQ cells were 62-fold resistant to trimetrexate and 68- and 96-fold cross-resistant to the other lipophilic antifolates metoprine and piritrexim (BW 301U). No cross-resistance was observed with vincristine or doxorubicin, and sensitivity was not increased with 5 micrograms/ml of verapamil, indicating that it was not a typical multidrug resistance phenotype. WI-L2/TMQ exhibited a 2-fold increase in dihydrofolate reductase; however, this did not contribute significantly to the observed resistance, since these cells retained full sensitivity to methotrexate. Nor were there any kinetic alterations in dihydrofolate reductase toward trimetrexate or differences in the levels of thymidylate synthase. The major difference between the sensitive and resistant cell line was a 50% decrease in the influx rate of WI-L2/TMQ cells which produced a corresponding decrease in cellular trimetrexate at the steady state. No difference in efflux rates was detected nor were there any differences in intracellular water or metabolism of trimetrexate. Additional characterization of trimetrexate transport in WI-L2 showed that influx was nonsaturable up to 5 mM extracellular trimetrexate, relatively insensitive to sodium azide, and exhibited a Q10 of 2.7. Influx was, however, inhibited in a dose-dependent manner by concentrations of p-chloromercuribenzylsulfonate above 10 microM. Efflux studies revealed a large nonexchangeable fraction of trimetrexate that was well above the dihydrofolate reductase binding capacity and varied depending on the initial level of cell-associated drug. The intracellular exchangeable trimetrexate concentration at the steady state was always several-fold higher than the extracellular concentration. Retention of trimetrexate appeared to be coupled to some component of energy metabolism, since the presence of sodium azide stimulated this process by 2- to 3-fold. The data suggest that trimetrexate enters cells by passive diffusion but then is distributed and concentrated within the cell through more complex mechanisms which may involve energy coupling, compartmentation, or binding to macromolecules or organelles, although some type of carrier-mediated process cannot be ruled out.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimetabolites, Antineoplastic↗

PubMed1986

Comparative evaluation of the effect of pharmacological agents on endocytosis and coendocytosis of IgE by rat basophilic leukaemia cells.

The aggregation of IgE bound to rat basophilic leukaemia (RBL) cells leads to the exocytosis of mediators, the endocytosis of the antigen-aggregated mouse IgE anti-DNP, as well as the coendocytosis of some unaggregated monomeric rat IgE (IR162) and/or unbound receptors. We describe here the relative effect on endocytosis and coendocytosis of various pharmacological agents that block or enhance exocytosis. We have previously shown that, unlike exocytosis, endocytosis by RBL and normal rat mast cells was independent of extracellular calcium. We show here that the presence of calcium chelators or antagonists also had no effect on endocytosis of cross-linked IgE. However, coendocytosis of non-cross-linked IgE was partially inhibited by the elimination of extracellular calcium and the addition of calcium chelators such as EDTA or EGTA-Mg2+. Moreover, the addition of calcium antagonists such as Ni2+ and Co2+ (5 mM) to an incubation mixture containing Ca2+ (1 mM) resulted in the complete inhibition of coendocytosis without affecting endocytosis. Other inhibitors of exocytosis such as sodium azide (10-2M), quercetin (10-4M) and dibutyryl cyclic AMP (10-2 M) blocked coendocytosis completely but had no effect on endocytosis. Sodium azide (10 mM) in combination with 2-deoxyglucose (10 mM) effectively inhibited (90%) endocytosis. Cytochalasin B (10-4 M), which was shown to enhance serotonin release, had no effect on the extent of endocytosis or coendocytosis observed 20 min after the initiation of aggregation. Thus, in RBL cells, endocytosis, coendocytosis and exocytosis exhibit distinguishable sensitivities to some pharmacological drugs.

Animals↗

PubMed1987

Biochemically damaged erythroblasts bind natural serum antibodies and activate complement.

Friend leukaemia erythroblasts which had been damaged biochemically by treatment with inhibitors of cellular metabolism (sodium fluoride, sodium azide) or of protein synthesis (cycloheximide, puromycin) were incubated with heat-inactivated or fresh mouse serum and tested for surface-bound IgG and C3c, respectively, by reaction with FITC-immunoconjugates followed by flow-cytofluorometry. Erythroblasts exposed to sodium azide, cycloheximide or puromycin showed specific binding of IgG; the extent of binding was related to the concentration of the drugs and duration of treatment. Moreover, prolonged exposure of the cells to the inhibitors of protein synthesis lead to a dose-dependent activation of complement. The results suggest that the opsonization of biochemically-damaged Friend leukaemia erythroblasts with IgG and C3 may facilitate their interaction with macrophages.

Antibodies, Anti-Idiotypic↗

PubMed1987

Use of a sensitive receptor binding assay to discriminate between full-length and truncated human recombinant tumor necrosis factor proteins.

A radioreceptor assay (RRA) capable of detecting picomolar concentrations of human recombinant tumor necrosis factor (TNF) was used to compare the relative binding affinities of genetically engineered full-length and truncated TNF proteins. The specific cell-surface receptors for TNF present on the human cervical carcinoma cell line ME-180 were characterized as having a Kd of 0.2 nM and a density of 2700 sites/cell. Conditions were then defined for an RRA that maximized the specific binding of 125I-TNF to this adherent cell line. Incubation of ME-180 cells with 125I-TNF at 37 degrees C in the presence of 0.02% sodium azide resulted in a 4-fold increase in assay sensitivity and a doubling of specific counts bound, as compared to binding done at 4 degrees C with or without sodium azide. Inhibition of receptor-ligand internalization under these conditions was a likely reason for the increases. This system was utilized to compare low concentrations of the full-length TNF protein and a genetically altered TNF protein (mutein) which lacks the 10 N-terminal amino acids and contains an N-terminal methionine. Previous studies showing the truncated TNF to be 2- to 3-fold lower in cytotoxic activity on a variety of tumor cell lines were corroborated by our findings that the mutein was also three and one-half times lower in relative affinity for the TNF receptor on ME-180 cells. These results suggest a possible role for these residues in receptor binding and illustrate the use of a highly sensitive RRA for the evaluation of TNF molecules altered by recombinant DNA technology.

Amino Acid Sequence↗

PubMed1983

Receptor-mediated endocytosis of transferrin in K562 cells.

Human diferric transferrin binds to the surface of K562 cells, a human leukemic cell line. There are about 1.6 X 10(5) binding sites per cell surface, exhibiting a KD of about 10(-9) M. Upon warming cells to 37 degrees C there is a rapid increase in uptake to a steady state level of twice that obtained at 0 degree C. This is accounted for by internalization of the ligand as shown by the development of resistance to either acid wash or protease treatment of the ligand-cell association. After a minimum residency time of 4-5 min, undegraded transferrin is released from the cell. Internalization is rapid but is dependent upon cell surface occupancy; at occupancies of 20% or greater the rate coefficient is maximal at about 0.1-0.2 min-1. In the absence of externally added ligand only 50% of the internalized transferrin completes the cycle and is released to the medium with a rate coefficient of 0.05 min-1. The remaining transferrin can be released from the cell only by the addition of ligand, suggesting a tight coupling between cell surface binding, internalization, and release of internalized ligand. There is a loss of cell surface-binding capacity that accompanies transferrin internalization. At low (less than 50%) occupancy this loss is monotonic with the extent of internalization. Even at saturating levels of transferrin, the loss of surface receptors upon internalization never exceeds 60-70% of the initial binding capacity. This suggests that receptors enter the cell with ligand but are replaced so as to maintain a constant, albeit reduced, receptor number on the cell surface. In the absence of ligand, the cell surface receptor number returns at 37 degrees C. Neither sodium azide nor NH4Cl blocks internalization of ligand. However, they both prevent the release of transferrin from the cell thus halting the transferrin cycle. Excess ligand can overcome the block due to NH4Cl but not azide although the cycle is markedly slower. Iron is delivered to these cells by transferrin at 37 degrees C with a rate coefficient of 0.15 to 0.2 min-1. The iron is released from the transferrin and the majority is found in intracellular ferritin. There is a large internal receptor pool comprising 70 to 80% of the total cell receptors and this may be involved in maintaining the steady state iron uptake.

Ammonium Chloride↗

PubMed1984

A study of the differential respiratory burst activity elicited by promastigotes and amastigotes of Leishmania donovani in murine resident peritoneal macrophages.

Acridine orange and ethidium bromide and a combination of fluorescent and transmitted light microscopy used in conjunction with the qualitative nitroblue tetrazolium assay for superoxide anion (O2-) release demonstrated dramatic differences in the binding of and respiratory burst (RB) activity elicited by promastigotes and amastigotes of Leishmania donovani in resident peritoneal macrophages (M phi) from C57BL/10ScSn mice. When amastigotes were incubated with M phi for 30 min the number of parasites per 100 M phi was 2-4-fold higher, a higher proportion of M phi became infected and the mean number of parasites per infected M phi was higher than in promastigote infections. RB activity was higher for promastigotes than amastigotes both in terms of the percentage of infected M phi containing formazan positive parasites and the percentage of individual formazan positive parasites. In an attempt to explain the differential response to promastigotes and amastigotes, RB activity was examined for sodium azide-treated, glutaraldehyde-fixed and heat-killed parasites and for various transformation intermediates between amastigotes and promastigotes. Binding and RB activity were also examined in conjunction with competitive binding assays designed to determine the specific receptors involved in ligand binding of both forms of the parasite to the M phi. The results indicate that, while amastigotes may possess an azide-sensitive mechanism which either competes for O2- produced or causes localized inactivation of RB activity, this cannot account for the full magnitude of the difference between the two forms of the parasite. The transformation and competitive binding studies suggest that the more likely explanation lies in both qualitative and quantitative differences in the distribution of surface ligands involved in binding the parasite to the M phi plasma membrane and that the well characterized mannose/fucose receptor may be important in promastigote, but not amastigote, binding and RB activity.

Animals↗

PubMed1994

[Energy-dependent Ca2+-transport in intracellular smooth muscle structures].

In experiments performed on digitonin-treated myometrium cells the existence of intracellular energy-dependent Ca(2+)-transporting system has been identified. The mitochondria-linked energy-dependent accumulation of Ca2+ was inhibited by ruthenium red and sodium azide with Ki of 0.7 +/- 0.3 microM and 1.1 +/- 0.4 mM, respectively. The Ca2+ ionophore A23187 added to the incubation medium following the termination of the accumulation process by ruthenium red caused a discharge of Ca2+ accumulated from the mitochondria. In the endoplasmic reticulum there exists a Mg2+,ATP-dependent Ca(2+)-pump which is potentiated by oxalate, immune to ruthenium red and sodium azide and inhibited by thapsigargin with Ki < 20 nM. In the absence of oxalate, the component of mitochondrial accumulation of Ca2+ was 3-4 times higher that of the endoplasmic reticulum. These results indicate that under the conditions used the calcium capacity of mitochondria was significantly higher than that of the endoplasmic reticulum. It is suggested that mitochondria serve as a high capacity intracellular Ca(2+)-accumulating store protecting smooth muscle cells from Ca2+ overload under some abnormal states. Under normal physiological conditions the endoplasmic reticulum serves as the major intracellular store involved in the pharmacomechanical coupling in the smooth muscle of the myometrium.

Adenosine Triphosphate↗

PubMed1995

Singlet oxygen generation in the superoxide reaction.

ESR spin trapping was utilized to study the singlet oxygen (1O2) generation in the reaction of superoxide (O2) with H2O2. The spin trap used was 2,2,6,6-tetramethyl-4-piperdone. Incubation of xanthine, xanthine oxidase and H2O2 generated 1O2 spin adduct signal. Omission of xanthine, xanthine oxidase or H2O2 caused a sharp decrease in 1O2 generation. 1O2 scavenger, sodium azide, inhibited 1O2 generation while .OH scavenger, ethanol, only slightly decreased the signal intensity. Potassium superoxide (KO2) decomposition generated 1O2. Catalase and sodium azide inhibited 1O2 generation and H2O2 enhanced it. The results demonstrate that O2 is capable of generating 1O2 upon reaction with H2O2.

Azides↗

PubMed1994

Bacterial translocation across enterocytes: results of a study of bacterial-enterocyte interactions utilizing Caco-2 cells.

Due to the inherent limitations of in vivo studies, the cellular mechanisms underlying the process of bacterial translocation (BT) across the intestinal epithelial barrier are poorly understood. Thus, we have utilized the Caco-2 intestinal cell line to study this process. Caco-2 cells were grown to confluence on semipermeable membranes contained in the upper compartment of a 2 compartment system. Cellular confluence and tight junction integrity was verified by measurements of the transepithelial electrical resistance in ohms cm2.BT was measured by culturing the bacteria (nonpathogenic Escherichia coli) that were able to cross the Caco-2 monolayer and were present in the bottom compartment, as well as by monitoring the passage of 1-micron fluorescent beads. Caco-2 cells were pretreated with several metabolic inhibitors: 1.0 mM sodium azide (oxidative phosphorylation), 10 micrograms/ml nocodazole (microtubule), 10 microM phalloidine (microfilament), and 5.0 micrograms/ml cytochalasin D (microfilament). To investigate the mechanisms of BT. Both bacteria and fluorescent beads crossed the Caco-2 monolayer. Azide had no effect on BT, while both nocodazole (n = 17) and phalloidine (n = 14) significantly decreased translocation of E. coli versus control monolayers (p < .05). Cytochalasin D increased BT versus control membranes, however this was associated with loss of tight junction integrity (transepithelial electrical resistance decreased from 201 +/- 79 to 87 +/- 6.4). BT across Caco-2 cells appears to be a polar process which is to some extent microtubule- and microfilament-dependent.

Azides↗

PubMedDate not supplied

[Development of a method for assessing viable Bifidobacterium in the preparation Bifikol].

The method has been developed for accounting viable bifidobacteria in the complex preparation biphicol using the growth inhibitor of Escherichia coli (0.01% solution of sodium azide), added to the growing medium. Choice of sodium azide concentration inhibiting growth of Escherichia coli M-17 and not affecting the growth of Bifidobacterium bifidum 1 is described in detail. Data are presented on the quality of commercial preparation made at different enterprises.

Azides↗

PubMed2000

Inhibition of UV irradiation-induced oxidative stress and apoptotic biochemical changes in human epidermal carcinoma A431 cells by genistein.

Ultraviolet (UV) light is a strong apoptotic trigger that can induce a caspase-dependent biochemical change in cells. We previously showed that UV irradiation can elicit caspase-3 activation and the subsequent cleavage and activation of p21-activated kinase 2 (PAK2) in human epidermal carcinoma A431 cells. We report that genistein, an isoflavone compound with known inhibitory activities to protein tyrosine kinases (PTKs) and topoisomerase-II (topo-II), can prevent UV irradiation-induced apoptotic biochemical changes (DNA fragmentation, caspase-3 activation, and cleavage/activation of PAK2) in A431 cells. Surprisingly, two typical PTK inhibitors (tyrphostin A47 and herbimycin A) and three known topo-II inhibitors (etoposide, daunorubicin, and novomycin) had no effect on UV irradiation-induced apoptotic biochemical changes, suggesting that the inhibitory effect of genistein is not dependent on its property as a PTK/topo-II inhibitor. In contrast, azide, a reactive oxygen species (ROS) scavenger, could effectively block the UV irradiation-induced apoptotic cell responses. Flow cytometric analysis using the cell-permeable dye 2',7'-dichlorofluorescin diacetate as an indicator of the generation of ROS showed that UV irradiation caused increase of the intracellular oxidative stress and that this increase could be abolished by azide, suggesting that oxidative stress plays an important role in mediating the apoptotic effect of UV irradiation. Importantly, the UV irradiation-induced oxidative stress in cells could be significantly attenuated by genistein, suggesting that impairment of ROS formation during UV irradiation is responsible for the antiapoptotic effect of genistein. Collectively, our results demonstrate the involvement of oxidative stress in the UV irradiation-induced caspase activation and the subsequent apoptotic biochemical changes and show that genistein is a potent inhibitor for this process.

Antineoplastic Agents↗

PubMed1979

Effect of uncouplers of oxidative phosphorylation on microtubule location and surface structure in murine mast cells.

"Uncouplers" of oxidative phosphorylation (sodium azide, DNP, and oligomycin) alter the location of microtubules within murine mast cells. Both cytoplasmic microtubules, perpendicular to the plasma membrane within cell surface folds, and intranuclear microtubules were observed. In addition, one or more dense plaque-like structures adjacent the plasma membrane in mast cells appeared following incubation in the antimetabolities. Intranuclear microtubules and cytoplasmic microtubules within the cell surface ridges disappeared in azide-treated mast cells that were reincubated or "recovered" in PBS. However, both these structures remained in oligomycin- and DNP-treated murine mast cells following reincubation.

Animals↗