Cyclic Hydroxylamines as Monitors of Peroxynitrite and Superoxide-Revisited

There is a considerable need for methods that allow quantitative determination in vitro and in vivo of transient oxidative species such as peroxynitrite (ONOOH/ONOO–) and superoxide (HO2•/O2•−). Cyclic hydroxylamines, which upon oxidation yield their respective stable nitroxide radicals, have been suggested as spin probes of peroxynitrite and superoxide. The present study investigated this approach by following the kinetics of peroxynitrite decay in the absence and presence of various 5-membered and 6-membered ring hydroxylamines, and comparing the yield of their respective nitroxides using electron paramagnetic spectroscopy. The results demonstrate that hydroxylamines do not react directly with peroxynitrite, but are oxidized to their respective nitroxides by the radicals formed during peroxynitrite self-decomposition, namely •OH and •NO2. The accumulated nitroxides are far below their expected yield, had the hydroxylamines fully scavenged all these radicals, due to multiple competing reactions of the oxidized forms of the hydroxylamines with •NO2 and ONOO–. Therefore, cyclic hydroxylamines cannot be used for quantitative assay of peroxynitrite in vitro. The situation is even more complex in vivo where •OH and •NO2 are formed also via other oxidizing reactions systems. The present study also compared the yield of accumulated nitroxides under constant flux of superoxide in the presence of various cyclic hydroxylamines. It is demonstrated that certain 5-membered ring hydroxylamines, which their respective nitroxides are poor SOD-mimics, might be considered as stoichiometric monitors of superoxide in vitro at highest possible concentrations and pH.

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Effect of pH and inhibitors on beta-amyloid fibril assembly

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166221 ◽

1996 ◽

Vol 54 ◽

pp. 752-753

Author(s):

Beverly E. Maleeff ◽

Timothy K. Hart ◽

Stephen J. Wood ◽

Ronald Wetzel

Keyword(s):

Amyloid Fibril ◽

Peptide Fragment ◽

Hydrophobic Peptides ◽

Amyloid Fibril Formation ◽

Effects Of Ph ◽

Severity Of The Disease ◽

Kinetics Of ◽

The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

Nuklearmedizin ◽

10.1055/s-0037-1620623 ◽

1977 ◽

Vol 16 (04) ◽

pp. 157-162 ◽

Cited By ~ 1

Author(s):

C. Schümichen ◽

B. Mackenbrock ◽

G. Hoffmann

Keyword(s):

Normal Saline ◽

Half Life ◽

Compound A ◽

Short Half Life ◽

Low Concentrations ◽

The Stability ◽

Kinetics Of ◽

In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

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Acquired Haemophilia: Functional Study of Antibodies to Factor VIII

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650189 ◽

1981 ◽

Vol 45 (03) ◽

pp. 285-289 ◽

Cited By ~ 14

Author(s):

J P Allain ◽

A Gaillandre ◽

D Frommel

Keyword(s):

Factor Viii ◽

Functional Study ◽

Factor Viii Inhibitor ◽

Acquired Haemophilia ◽

Viii Inhibitor ◽

Kinetics Of ◽

Antibody Function ◽

Native Plasma

SummaryFactor VIII complex and its interaction with antibodies to factor VIII have been studied in 17 non-haemophilic patients with factor VIII inhibitor. Low VIII:C and high VIIIR.Ag levels were found in all patients. VIII:WF levels were 50% of those of VTIIRrAg, possibly related to an increase of poorly aggregated and electrophoretically fast moving VIIIR:Ag oligomers.Antibody function has been characterized by kinetics of VIII :C inactivation, saturability by normal plasma and the slope of the affinity curve. Two major patterns were observed:1) Antibodies from 6 patients behaved similarly to those from haemophiliacs by showing second order inhibition kinetics, easy saturability and steep affinity slope (> 1).2) Antibodies from other patients, usually with lower titres, inactivated VIII :C according to complex order kinetics, were not saturable, and had a less steep affinity slope (< 0.7). In native plasma, or after mixing with factor VIII concentrate, antibodies of the second group did not form immune complexes with the whole factor VIII molecular complex. However, dissociation procedures did release some antibodies from apparently low molecular weight complexes formed in vivo or in vitro. For appropriate management of non-haemophilic patients with factor VIII inhibitor, it is important to determine the functional properties of their antibodies to factor VIII.

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ДИНИТРОЗИЛЬНЫЕ КОМПЛЕКСЫ ЖЕЛЕЗА C ТИОЛСОДЕРЖАЩИМИ ЛИГАНДАМИ ПРЕДСТАВЛЕНЫ В ЖИВЫХ ОРГАНИЗМАХ В ОСНОВНОМ ИХ БИЯДЕРНОЙ ФОРМОЙ

Биофизика ◽

10.31857/s0006302920060149 ◽

2020 ◽

Vol 65 (6) ◽

pp. 1142-1153

Author(s):

В.Д. Микоян ◽

◽

Е.Н. Бургова ◽

Р.Р. Бородулин ◽

А.Ф. Ванин ◽

...

Keyword(s):

Electron Paramagnetic Resonance ◽

Sodium Nitrite ◽

Iron Complexes ◽

Paramagnetic Resonance ◽

First Case ◽

Dinitrosyl Iron ◽

Electron Paramagnetic ◽

Dinitrosyl Complexes

The number of mononitrosyl iron complexes with diethyldithiocarbamate, formed in the liver of mice in vivo and in vitro after intraperitoneal injection of binuclear dinitrosyl iron complexes with N-acetyl-L-cysteine or glutathione, S-nitrosoglutathione, sodium nitrite or the vasodilating drug Isoket® was assessed by electron paramagnetic resonance (EPR). The number of the said complexes, in contrast to the complexes, formed after nitrite or Isoket administration, the level of which sharply increased after treatment of liver preparations with a strong reducing agent - dithionite, did not change in the presence of dithionite. It was concluded that, in the first case, EPR-detectable mononitrosyl iron complexes with diethyldithiocarbamate in the absence and presence of dithionite appeared as a result of the reaction of NO formed from nitrite with Fe2+-dieth- yldithiocarbamate and Fe3+-diethyldithiocarbamate complexes, respectively. In the second case, mononitrosyl iron complexes with diethyldithiocarbamate appeared as a result of the transition of iron-mononitosyl fragments from ready-made iron-dinitrosyl groups of binuclear dinitrosyl complexes, which is three to four times higher than the content of the mononuclear form of these complexes in the tissue...

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In vitro/in vivo correlations in the kinetics of poly (lactide-co-glycolide) (PLG) delivery systems of GnRH peptides

Journal of Controlled Release ◽

10.1016/0168-3659(92)90053-t ◽

1992 ◽

Vol 21 (1-3) ◽

pp. 213

Author(s):

H. Berger ◽

K. Fechner ◽

N. Heinrich ◽

D. Lorenz ◽

E. Albrecht ◽

...

Keyword(s):

Delivery Systems ◽

Kinetics Of

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SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO. II

The Journal of General Physiology ◽

10.1085/jgp.16.2.233 ◽

1932 ◽

Vol 16 (2) ◽

pp. 233-242 ◽

Cited By ~ 27

Author(s):

B. G. Wilkes ◽

Elizabeth T. Palmer

Keyword(s):

Physiological Activity ◽

Outer Region ◽

Living Cells ◽

Yeast Cells ◽

Live Cells ◽

Intracellular Enzyme ◽

Relationship Of ◽

Kinetics Of

1. The pH-activity relationship of invertase has been studied in vivo and in vitro under identical external environmental conditions. 2. The effect of changing (H+) upon the sucroclastic activity of living cells of S. cerevisiae and of invertase solutions obtained therefrom has been found, within experimental error, to be identical. 3. The region of living yeast cells in which invertase exerts its physiological activity changes its pH freely and to the same extent as that of the suspending medium. It is suggested that this may indicate that this intracellular enzyme may perform its work somewhere in the outer region of the cell. 4. In using live cells containing maltase, no evidence of increased sucroclastic activity around pH 6.9, due to the action of Weidenhagen's α-glucosidase (maltase), was found.

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In vivo assessment of human vaginal oxygen and carbon dioxide levels during and post menses

Journal of Applied Physiology ◽

10.1152/japplphysiol.01422.2004 ◽

2005 ◽

Vol 99 (4) ◽

pp. 1582-1591 ◽

Cited By ~ 32

Author(s):

Donna R. Hill ◽

Marianne E. Brunner ◽

Deborah C. Schmitz ◽

Catherine C. Davis ◽

Janine A. Flood ◽

...

Keyword(s):

Animal Studies ◽

Pathogenic Bacteria ◽

Sensor Technology ◽

Atmospheric Conditions ◽

Bacterial Virulence Factor ◽

Carbon Dioxide Levels ◽

Kinetics Of ◽

Insertion Process

Previous in vitro and in vivo animal studies showed that O2and CO2concentrations can affect virulence of pathogenic bacteria such as Staphylococcus aureus. The objective of this work was to measure O2and CO2levels in the vaginal environment during tampon wear using newly available sensor technology. Measurements by two vaginal sensors showed a decrease in vaginal O2levels after tampon insertion. These decreases were independent of the type of tampons used and the time of measurement (mid-cycle or during menstruation). These results are not in agreement with a previous study that concluded that oxygenation of the vaginal environment during tampon use occurred via delivery of a bolus of O2during the insertion process. Our measurements of gas levels in menses showed the presence of both O2and CO2in menses. The tampons inserted into the vagina contained O2and CO2levels consistent with atmospheric conditions. Over time during tampon use, levels of O2in the tampon decreased and levels of CO2increased. Tampon absorbent capacity, menses loading, and wear time influenced the kinetics of these changes. Colonization with S. aureus had no effect on the gas profiles during menstruation. Taken collectively, these findings have important implications on the current understanding of gaseous changes in the vaginal environment during menstruation and the potential role(s) they may play in affecting bacterial virulence factor production.

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Measurements of the jejunal unstirred layer in normal subjects and patients with celiac disease

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1996.270.3.g487 ◽

1996 ◽

Vol 270 (3) ◽

pp. G487-G491 ◽

Cited By ~ 4

Author(s):

A. Strocchi ◽

G. Corazza ◽

J. Furne ◽

C. Fine ◽

A. Di Sario ◽

...

Keyword(s):

Celiac Disease ◽

Layer Thickness ◽

Villous Atrophy ◽

Normal Subjects ◽

Unstirred Layer ◽

Maximal Velocity ◽

Normal Rat ◽

Kinetics Of

Normal intestinal absorption of nutrients requires efficient luminal mixing to deliver solute to the brush border. Lacking such mixing, the buildup of thick unstirred layers over the mucosa markedly retards absorption of rapidly transported compounds. Using a technique based on the kinetics of maltose hydrolysis, we measured the unstirred layer thickness of the jejunum of normal subjects and patients with celiac disease, as well as that of the normal rat. The jejunum of humans and rats was perfused with varying maltose concentrations, and the apparent Michaelis constant (Km) and maximal velocity (Vmax) of maltose hydrolysis were determined from double-reciprocal plots. The true Km of intestinal maltase was determined on mucosal biopsies. Unstirred layer thickness was calculated from the in vivo Vmax and apparent Km and the in vitro Km of maltase. The average unstirred layer thickness of 11 celiac patients (170 micron) was seven times greater than that of 3 controls (25 micron). The unstirred layer of each celiac exceeded that of the controls. A variety of factors could account for the less efficient luminal stirring observed in celiacs. Although speculative, villous contractility could be an important stirring mechanism that would be absent in celiacs with villous atrophy. This speculation was supported by the finding of a relatively thick unstirred layer (mean: 106 micron) in rats, an animal that lacks villous contractility. Because any increase in unstirred layer slows transport of rapidly absorbed compounds, poor stirring appears to represent a previously unrecognized defect that could contribute to malabsorption in celiac disease and, perhaps, in other intestinal disorders.

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Cell kinetics of human tumors by in vitro bromodeoxyuridine labeling.

Journal of Histochemistry & Cytochemistry ◽

10.1177/37.9.2768814 ◽

1989 ◽

Vol 37 (9) ◽

pp. 1449-1454 ◽

Cited By ~ 60

Author(s):

J S Meyer ◽

J Nauert ◽

S Koehm ◽

J Hughes

Keyword(s):

Tritiated Thymidine ◽

S Phase ◽

Dna Flow Cytometry ◽

Breast Carcinomas ◽

Brdu Labeling ◽

The Central Nervous System ◽

Labeling Method ◽

Kinetics Of

We labeled active S-phase cells in primary breast carcinomas with a modified 5-bromo-2'-deoxyuridine (BrdU) procedure using a silver-enhanced colloidal gold visualization step. Separate samples of 29 tumors were labeled with BrdU or tritiated thymidine ([3H]-dThd), and the labeling indices (LI) from the two methods were equivalent (Spearman's correlation coefficient = 0.96). Three breast carcinomas were incubated in various mixes of both BrdU and [3H]-dThd and developed sequentially for each. Paired photomicrographs showed that the same nuclei were labeled by either precursor. The in vitro method yielded LIs similar to those reported after in vivo pulse BrdU labeling for tumors of the central nervous system. The BrdU LI correlated significantly (r = 0.76, p less than 0.001) with % S-phase by DNA flow cytometry in 33 breast carcinomas. The BrdU labeling method is simpler and more rapid than the [3H]-dThd procedure (1-2 days for completion for the former, 7-10 days for the latter), and it provides an equivalent measurement of proliferative index.

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