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At least 127 records · Page 7Linked to original sources
PubMed1993

[Mechanism of the cytologic action of streptolysin O: effect of scavengers of active oxygen species and complexons on erythrocyte hemolysis].

The hemolysis of rabbit erythrocytes, initiated by streptolysin O purified samples, is appreciably suppressed in the presence of the scavengers of singlet oxygen (sodium azide, histidine, tryptophan), .OH-radical (ethanol, mannitol), O.(2-)-radical (nitrotetrazolium blue, streptokinase), chelating agents (o-phenanthroline, sodium diethyldithiocarbamate) and some oxidoreductants such as K3FeCN6 and riboflavin as well. The streptolysin O hemolytic effect is supposed to be realized due to the participation of active oxygen species and this phenomenon depends upon the presence of the transition metals in the system.

Animals↗
PubMed1990

Triple bone labeling of canine mandibles.

Fluorescence microscopy was used for evaluation of new bone formation in 16 canine mandibles augmented with hydroxylapatite (HA) granules. Three fluorochromes were injected at different time intervals during therapeutic radiation treatment. Oxytetracycline, DCAF, and alizarin-complexone were given intravenously to mark the bone level at these times, respectively. Oxytetracycline, which defined the baseline of bone at implantation of HA, was detectable in 42% of animals that were irradiated and in no animal of the nonirradiated control group. The marker DCAF, designating levels of bone at the start of radiation, was demonstrated in 92% of irradiated animals, and in 75% of animals in the control group. The uptake of alizarin-complexone determined the level of bone found at the end of irradiation. This marker was demonstrated in 50% of the dogs irradiated and in 75% of the control dogs. Bony trabeculae were found between and at the surface of the HA granules. New generation of bone directly on the HA granule and in the surrounding haversian systems as part of normal bone turnover was demonstrated to take place more than 5 months after implantation of HA.

Alveolar Bone Loss↗
PubMed1995

Effect of anthraquinone derivatives on lipid peroxidation in rat heart mitochondria: structure-activity relationship.

Lipid peroxidation was induced in rat heart mitochondria with FeSO4 and the inhibitory effects of various anthraquinone derivatives were compared. Oxygen consumption and malondialdehyde formation were used to quantitate the amount of lipid peroxidation. Emodin [2], alizarin [13], and alizarin complexone [14] significantly inhibited lipid peroxidation; their potency as inhibitors of lipid peroxidation was higher than that of alpha-tocopherol. Structure-activity analysis showed that two hydroxyl groups arranged in either the ortho- or meta-position in the C ring of the anthraquinone nucleus are required for such derivatives to inhibit lipid peroxidation. The diphenyl-p-picrylhydrazyl test showed that alizarin [13] and alizarin complexone [14] are free-radical scavengers while emodin [2] is not. The mechanism for emodin [2] to inhibit lipid peroxidation is most likely due to inhibition on the propagation of lipid peroxyl radicals in the mitochondrial membrane.

Animals↗
PubMed2004

A simple and non-radioactive technique to study the effect of monophosphoesters on matrix vesicle-mediated calcification.

A simple and non-radioactive technique based on O-cresolpthalein complexone assay was developed to study in vitro non-radioactive calcium ((40)Ca) deposition by isolated matrix vesicles. Using this technique, the effect of various phosphoester substrates including ATP, AMP and beta-GP on in vitro MV-calcification was studied. O-cresolpthalein complexone assay with non-radioactive calcium demonstrated that AMP or beta-GP were more effective in promoting calcium deposition by isolated MVs than ATP. The application of this non-radioactive technique, which is highly sensitive and simple, would offer a useful alternative approach to the routinely used radiometric biomineralization assay which employs radioactive (45)Ca.

Journal Article↗
PubMed1992

[The effect of Ca-diethylenetriamine pentaacetate on the bio-behavior of tumor-affine metal complexes].

The complexon CaDTPA was injected into tumour-bearing mice in concentrations of 0.05, 0.1, 0.3, and 0.6 mole/l (pH:6) 30 min after the 169Yb-injection. 100 microliters of a 0.3 M CaDTPA solution were injected at different time points (simultaneously, 2, 5, 10, 20, 30, 40 and 50 min, 1, 1.25, 1.5, 2.5 and 10 h) after 169Yb-citrate injection. The animals were killed 24 h after radionuclide administration. A strong radioactivity decrease was observable 24 h p.i. not only in blood, liver, spleen, muscle and bone but also in the tumour if CaDTPA was administered within the first 2 h after ytterbium injection. Thereafter no change in radioactivity could be achieved by DTPA. A time phase in which the Yb could be eliminated from the tissues by means of DTPA (time intervals < 2 h) was distinguishable from a time phase in which it was not attainable for DTPA (time intervals > 5 h). This indicates that the incorporation of Yb into the cells is completed after 5 h and that the metals are intracellularly bound, probably to the lysosomes. Improvements of the scintigraphic tumour detection cannot be expected from the use of complexons.

Animals↗
PubMedDate not supplied

[The design and trial of conjugates for performing lanthanide immunofluorescence analysis].

The possibility of using a number of complexons for labeling of antibodies to Venezuelan equine encephalomyelitis virus and to adenovirus with europium ions was studied. The resultant conjugates, irrespective of the type of complexon, were shown to retain their immunochemical activity and could be used for lanthanide immunofluorescence analysis of virus-specific antigens.

Adenoviridae↗
PubMedDate not supplied

[Effect of diethylene-triaminopentamethylphosphonic acid complex on various hematologic and biochemical indicators in experimental animals].

A successive triple introduction of organophosphorus complexon DTPP (sodium-dicalcium salt of diethylene-triaminopentamethylphosphonic acid) in a dose of 500 mg/kg to albino male rats did not produce any marked effect on the composition of the peripheral blood. Some shortening of the initial period in blood coagulation process was noted. DTPP produced a moderate stimulation of the iron-containing enzymes (catalase, peroxidase, cytochroxidase) which led to an increased oxygen consumption. The blood serum and urine potassium, sodium and calcium content did not undergo any significant changes, while the magnesium concentration in the blood serum dropped by 37 pc and in the urine rose by as much as twice as compared to controls. This bears evidence to an elevated discharge of magnesium from the organism following the action of the DTPP complexon.

Adenosine Triphosphatases↗
PubMed2001

Effect of polymethylmethacrylate particles on mature bone in the optical bone chamber.

Reaction of mature bone and its vasculature to 3.33 +/- 0.19 microm polymethylmethacrylate (PMMA) particles at a concentration of 2.5 x 10(8)/cc was measured using optical bone chamber implant intravital microscopy. Twelve adult female New Zealand White rabbits were divided into six receiving Healon alone (controls) and six receiving Healon plus PMMA. The particles were introduced to the bone chamber compartment after removing its overlying optical element, which was immediately reinstalled. Reaction was monitored weekly over a 6-week period using video and photographic imaging. Bone was labeled before treatment with oxytetracycline and after treatment with alizarin complexone. Perfusing blood was labeled with fluorescein isothiocyanate dextran-70 kDa (FITC-D70). Parameters measured were net bone resorption, from black and white images, bone turnover, from color images, vascularity, and average vessel caliber. Neither bone turnover nor vessel caliber were significantly affected at the p < or = 0.050 level over time. In contrast, bone resorption was significantly greater and vascularity significantly less in the presence of PMMA. It was inferred that any differences in bone turnover were masked by resorption of new bone. It was concluded that the lack of a PMMA effect on average vessel caliber meant that the vascularity effects were not due to angiogenesis, but to vessel recruitment (or its opposite), an effect more consistent with inflammation than repair. The lack of vascularity increase in PMMA-treated compartments also suggested that increased resorption was a local phenomenon, because blood supply had not increased to provide the extra osteoclasts required for observed net bone loss.

Animals↗
PubMed2007

Osteoblastic response to collagen scaffolds varied in freezing temperature and glutaraldehyde crosslinking.

Collagen sponges are widely used scaffolds in bone engineering. To form bone, the osteoblastic cells undergo proliferation, differentiation, and mineralization stages in the scaffold. Crosslinking and freezing temperature are two important variables in fabricating collagen sponges. The purpose of this study was to examine the osteoblastic responses to collagen sponges prepared with or without glutaraldehyde crosslinking at different freezing temperatures (-20 degrees C or -80 degrees C). MC3T3-E1 osteoblastic cells were cultured in differently prepared sponges. Osteoblastic responses examined included cell numbers, osteocalcin expression, and calcium deposition. Cell numbers were measured by DNA content. Osteocalcin expression was determined by RT-PCR and real-time RT-PCR. Calcium deposition was assayed by ortho-cresophthalein complexone method and von Kossa stain. The osteoblastic cells grown in all collagen sponges did not show apparent signs of cytotoxicity. Collagen sponges differed in freezing temperatures resulted in similar osteoblastic responses. Glutaraldehyde-crosslinked sponges demonstrated less cell-mediated contraction and more cell numbers at day 7 (p < 0.005). However, they showed lower osteocalcin expression at day 7 (p < 0.05) and less calcium deposition at day 21 (p < 0.001). In summary, different freezing temperatures played a minor role in osteoblastic responses. Glutaraldehyde crosslinking process, though improved the dimensional stability of collagen sponges, might compromise the osteoblastic differentiation and mineralization.

3T3 Cells↗
PubMed2000

Sequential labelling of microdamage in bone using chelating agents.

Basic fuchsin labels microcracks, but a series of stains is required to differentiate between preexisting and test-induced microcracks and to label their growth in vitro. Basic fuchsin and five chelating agents-alizarin complexone, calcein, calcein blue, oxytetracycline, and xylenol orange-were randomly assigned to label microcracks in sequential rib sections from 10 donors. The density, length, and location of the microcracks did not differ significantly between the six stains, suggesting that each was equally effective in detecting microcracks. Paired specimens of trabecular bone were machined from bovine tibiae, stained with oxytetracycline, and fatigued in compression. One specimen from each pair was then stained with xylenol orange. Preexisting microdamage was stained with oxytetracycline, propagating microcracks with both stains and new, test-initiated damage with xylenol orange. Chelating agents are site-specific markers of the initiation and growth of microcracks.

Bone and Bones↗
PubMed1993

Purification and chemical characterization of staphyloferrin B, a hydrophilic siderophore from staphylococci.

This paper describes the chemical characterization of staphyloferrin B, a new complexone type siderophore isolated from low iron cultures of Staphylococcus hyicus DSM 20459. Purification of the very hydrophilic metabolite was achieved by anion exchange high performance liquid chromatography HPLC. Mass spectrometry showed a molecular mass of 448 amu. Hydrolysis with 8 M HCl revealed the presence of L-2,3-diaminopropionic acid, citrate, ethylenediamine and succinic semialdehyde. The connections between the four building blocks were determined by two-dimensional nuclear magnetic resonance measurements. UV/Vis and circular dichroism spectra are consistent with the proposed structure, which could also be confirmed by precursor feeding. The siderophore activity of staphyloferrin B was demonstrated by iron transport measurements.

Citrates↗
PubMed2005

Proliferation and osteogenic differentiation of mesenchymal stem cells cultured onto three different polymers in vitro.

In this study, the osteoinductive and cell-binding properties of three different resorbable polymers were evaluated by human mesenchymal stem cells (MSCs). MSCs were isolated, expanded, and cultivated onto resorbable D,D,L,L-polylactide (PLLA), collagen I/III, and polygalactin-910/polydioxanone (PGPD) scaffolds in vitro. To evaluate the influence of dexamethasone, ascorbic acid, and beta-glycerolphosphate (DAG) on osteoblast differentiation, MSCs were incubated in a DAG-enriched medium. After a 28-day period in vitro, the cellular loaded polymers were digested enzymatically by papain and HCl. The Ca(2+) content of the biomembranes was evaluated by an o-kresolphthalein-complexon reaction via photometer. A PicoGreen assay was performed for dsDNA quantification. Significant differences between the number of adherent MSCs were documented (collagen > PLLA > PGPD). Compared to the initial number of adherent cells, all biomaterials induced a significant decrease in cellular adherence after 28 days in vitro. The presence of DAG-enriched culture medium stimulated the cellular proliferation for PLLA and slightly for PGPD, whereas cell proliferation was inhibited when MSCs were cultivated onto collagen I/III. In comparison with the control groups, all biomaterials (PLLA, PGPD, and collagen I/III) showed a significant increase in local Ca(2+) accumulation under DAG stimulation after 28 days in vitro. Furthermore, collagen I/III and PLLA scaffolds showed osteoinductive properties without DAG stimulation. These results were verified by immunocytochemical stainings against osteoblast-typical markers (osteopontin and alkaline phosphatase) and completed by calcified matrix detection (von Kossa staining). MSCs were identified by CD105 and CD13 antigen expression. Corresponding to an absence of CD34, CD45, and collagen II expression, we found no chondrogenic or hematopoietic cell differentiation. The results indicate significant differences for the proliferation, differentiation, adherence, and Ca(2+) accumulation between the tested polymers in a MSC culture.

Biocompatible Materials↗
PubMed1991

Reversible inactivation of rat liver inorganic pyrophosphatase by substrate and its analogs.

Dissociation of Mg2+ from one of the two metal-binding sites whose occupancy is absolutely required for catalysis by rat liver inorganic pyrophosphatase is a slow reaction (tau 1/2 = 3 h). Polycarboxylic Mg2+ complexons markedly accelerate this process due to their binding with Mg2+ on the enzyme. PPi, ATP and a number of diphosphonate analogs of PPi also bind with Mg2+ on the enzyme with concomitant decrease in enzyme activity by 75% but do not release the bound Mg2+. The resulting ternary complex rapidly (tau 1/2 of several seconds) dissociates upon dilution into substrate-free medium. PPi and imidodiphosphate, which are substrates for pyrophosphatase, decrease the rate of reactivation by at least two orders of magnitude. The results can be explained by existence of two interconvertible forms of the enzyme, of which one is inactive and is stabilized by substrate or its analogs.

Chelating Agents↗
PubMed1978

Selective ion binding and membrane activity of synthetic cyclopeptides.

Four cyclic peptides related to the membrane-active complexones PV, cyclo-(L-Pro-Lval-D-Pro-D-Val)3, and valinomycin were synthesized: (1) cyclo-(L-Pro-L-Ala-D-Val)3 or PVPA, (2) cyclo-(L-Ala-L-Val-D-Pro-D-Val)3 or PVAV, (3) cyclo-(L-Pro-L-Val-D-Pro-D-Val)2-L-Pro-D-Val or PV-10, (4) cyclo-(L-Pro-L-Val-D-Pro-D-Val)2 or PV-8. In a two-phase extraction assay the affinity of PV and PVPA for alkali picrates was about three orders or magnitude greater than that of valinomycin. It was about equal to valinomycin for PVAV and much lower for PV-10 and PV-8. PV, PVPA and PVAV showed a selectivity sequence similar to that of valinomycin, namely K+ approximately Rb+ greater than Cs+ greater than Na+ greater than Li+. In the series PV, PV-10, PV-, the preference for K+ over Na+ was 700, 5 and less than 1, respectively. Thus, it was possible to reverse the selectivity of PV for K+ over Na+ by reducing the ring size from 12 to 8 amino acid residues. In sheep red cell lipid bilayer membranes PVPA increased the membrane conductance significantly in the presence of either KCl or NaCl but it was less potent than PV. PV-10, PV-8 and PVAV on the other hand were ineffective in this assay. The inactivity of PVAV as a potassium carrier in membrane was in contrast to its high affinity for potassium picrate in two-phase assays. Such a behaviour may be observed of a compound that has too low an aqueous cation binding constant to use the solution-complexation mechanism of PV (Davis et al. (1976) Biochemistry 15, 768--774 and Pinkerton et al. (1969) Biochem. Biophys. Res. Commun. 35, 512--518) and too slow binding and release kinetics to use the interfacial-complexation mechanism of valinomycin.

Cations, Monovalent↗
PubMed1977

A simple automated method for the fluorometric titration of calcium in biological fluids,.

A new automatic device has been developed for the determination of the calcium content in biological fluids. The method is based on a fluorometric titration technique, in which calcium is titrated with ethyleneglycolbis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). The end-point of the titration is indicated by quenching of the fluorescence of a calcium-calcein complex, in which calcein is the fluorescein-complexone indicator. To obtain proper results we found it necessary to use a 1 molar potassium hydroxide solution as titration medium. The results are printed out directly in concentration units (mmol/l). In order to carry out these determinations, several electronic and mechanical devices, including a sample-changer, titration cabinet with built-in fluorometer, control unit and electron titrator, were developed. Together they form the new calcium automatic device of which several qualitites such as precision, recovery and correlation have been studied. The disturbing influence of bilirubin has been minimized by using an excitation wavelength of 492 nm, at which there is nearly no absorption by bilirubin. At a concentration of bilirubin of as much as 500 micronmol/l, the recovery of calcium is still about 96%.

Autoanalysis↗
PubMed1990

A time-resolved fluoroimmunoassay for the determination of prostaglandin F2 alpha.

We describe a solid-phase immunoassay based on fluorescence detection for Prostaglandin F2 alpha (PGF2 alpha). Europium was used as the fluorescence marker. Prostaglandin F2 alpha was covalently bound to poly-L-lysine (PL) and labelled by coupling Eu3+ via the complexonate diethylenetriaminepentaacetic acid (DTPA). The labelled PGF2 alpha was tested in a competitive immunoassay. The detection limit for PGF2 alpha was about 2.2 pg per microtiter well. The intraassay-variation was 17.2% at 1.1 pg, 4.1% at 10 pg and 7.6% at 90 pg. The precision was determined by measuring various amounts of unlabelled PGF2 alpha (2.5 to 2,400 pg) in the assay buffer. The regression line for these studies resulted in a good correlation (y = 1.01x +/- 0.03; r = 0.996; n = 21). The results of a radioimmunoassay and of the fluoroimmunoassay were similar (y = 0.983 +/- 0.04; r = 0.988; n = 15). The new method enables PGF2 alpha analyses at concentrations in the fmolar range.

Animals↗
PubMed1990

Defective gap-junctional communication associated with imaginal disc overgrowth and degeneration caused by mutations of the dco gene in Drosophila.

The lethal(3)discs overgrown (dco) locus of Drosophila melanogaster, located on the third chromosome at cytogenetic position 100A5,6-100B1,2, is necessary for normal development and growth control in the imaginal discs of the larva. Three recessive lethal alleles (dco2, dco3, and dco18) in heteroallelic combinations and one allele (dco3) when homozygous cause the imaginal discs to continue to grow beyond the normal disc-intrinsic limit during an extended larval period. Some degeneration also occurs in the overgrowing discs. The discs overgrow even when transplanted early in their development into wild-type hosts, whereas normal discs stop growth at about the normal final size under such conditions, indicating that the overgrowth is a disc-autonomous effect of the mutations. During overgrowth the imaginal discs retain their single-layered epithelial structure except near regions of degeneration, and they differentiate into disc-appropriate but abnormal adult structures when transplanted into wild-type larval hosts. When the mutant larvae are reared under certain conditions a small percentage develop to the pharate adult stage, and these animals show a characteristic syndrome of abnormalities including swollen leg segments with many extra bristles, small or missing eyes, duplicated antennae and palpi, and separated vesicles of cuticle. A fourth recessive lethal allele (dcole88), when homozygous or in heteroallelic combination with the overgrowth alleles, causes the imaginal discs to degenerate, producing a "discless" phenotype. Gap junction-mediated communication was assayed by observing the intercellular transfer of injected fluorescein complexon (dye coupling). Dye coupling in the imaginal discs of the dco genotypes that cause overgrowth was dramatically reduced at 4 days after egg laying (AEL) compared with wild-type controls. Coupling was more normal although still significantly reduced at 7-8 and 12-14 days AEL. In c43hs1, another disc overgrowth mutant, the imaginal disc cells also showed very reduced dye coupling at 4 days and incomplete coupling at 9 days. In contrast, discs from wild-type larvae, two other imaginal disc overgrowth mutants, and a cell death mutant showed extensive dye coupling at all stages tested. Electron microscopic morphometry revealed a reduction in gap-junction length per unit lateral plasma membrane length in dco3/dco18 and c43hs1 wing discs, although not in dco2/dco3, compared with wild-type wing discs. The results suggest that gap-junctional cell communication may be involved in the cell interactions that limit cell proliferation in vivo.

Alleles↗