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PubMed2005

Deposition of insulin powders for inhalation in vitro and pharmacodynamic evaluation of absorption promoters in rats.

AIM: To prepare insulin powder for inhalation by spray-drying technology, determine the deposition of the insulin powder formulation in vitro and preliminarily investigate hypoglycemic response of the dry powder with/without absorption promoters. METHODS: The depositions of the insulin powder for inhalation were determined by the China Pharmacopoeia 2000 version addenda XH and hypoglycemic effects were evaluated by testing serum glucose with glucose oxidase-peroxidase (GOD-PAP) method. RESULTS: The depositions of the spray-dried insulin powder for inhalation were more than 40% under various humidity and their changes were not significant when air flow was no less than 18 L x min(-1). The coadministration of insulin with 8 mmol x L(-1)/dose sodium taurocholate [PA = 59.91%, Cnadir = (33 +/- 6) %] and 10 mmol x L(-1)/dose sodium deoxycholate [PA = 47.46% , Cnadir = (32 +/- 7)%] induced a significantly greater decline in blood glucose levels, while coadministration with 1% sodium caprylate, 1% sodium dodecyl sulfate, 250 microg/dose lecithin, 10 mmol x L(-1)/dose EDTA appeared to have no significant effect (P > 0.05). CONCLUSION: Insulin powder for inhalation was relatively stable under various humidity conditions and different flow current. The use of 8 mmol x L(-1)/dose sodium taurocholate and 10 mmol x L(-1)/dose sodium deoxycholate could be able to potentially improve the bioavailability of insulin by pulmonary route.

Administration, Inhalation↗
PubMed1975

Oxidative enzymes in the development of Fasciola hepatica L. V. Activity of oxidases and dehydrogenases in the Cercaria and Metacercaria.

The object of the study was the investigation of the occurrence and localization of oxidative enzymes in the 4th and 5th larval stages of the liver fluke, i. e. in the cercaria and metacercaria. The following enzymes were detected: cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases/diaphorases) as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde phosphate, glucose-6-phosphate, 6-phosphogluconate, beta-hydroxybutyrate, L-glutamate and alcohol dehydrogenases. The occurrence and localization of the enzymes were investigated histochemically in the cercaria still unreleased from the snail tissues, in the free natatorial cercaria, and in the encysted specimen, i.e. metacercaria. Among the enzymes studied only peroxidase was found to be absent from the cercaria and metacercaria, the latter larva being deprived of alcohol and L-glutamate dehydrogenases as well. The aerobic path, i.e. the Krebs cycle, was ascertained as the principal mode of obtaining energy in the free natatorial cercaria and metacercaria, and glycolysis as the main energy path for the undetached larva. The analysis of the above-mentioned oxidative enzymes was the basis for the description, within the available range, of the function and metabolism of individual organs of cercaria in different periods of its development. In the recapitulation the author discusses the effect of the parasitic way of life of the larval forms of Fasciola hepatica on their energy metabolism.

Alcohol Oxidoreductases↗
PubMed1990

Structure and histochemistry of the sublingual salivary glands of the one-humped camel (Camelus dromedarius).

Morphometric, histological and histochemical studies were carried out on the sublingual salivary glands of the Arabian camel (Camelus dromedarius). The glands are of the tubulo-acinar type and consist of many lobules that are composed of two types of cells, mucoserous and seromucous. The mucoserous cells form the main secretory units of the gland but seromucous cells are much more seldom and form associated acini. The former cells secrete and elaborate large quantities of neutral mucosubstances, sialomucins and little sulphomucins while only the apical portion of the latter cells shows weak to moderate activity for neutral and acid mucosubstances. The histoenzymological tests employed here detected a considerable activity of alkaline phosphatase, succinic dehydrogenase, aminopeptidase and non-specific esterases, but weak activities of cytochrome oxidase, peroxidase and no activities of triacylglycerol lipase, beta-glucoronidase and amylase. The functional significance of these findings is discussed.

Animals↗
PubMed1977

An improved technique for the rapid continuous measurement of whole blood glucose, suitable for clinical application in an artificial endocrine pancreas.

An improved bedside technique for the continuous monitoring of glycemia is described. A linear relationship results between whole blood glucose concentration and plasma glucose levels, and allows the calibration of the system in terms of plasma glucose levels. In operation venous blood is withdrawn at a steady rate using a double-lumen catheter and directed to a continuous-flow laboratory analyzer, where glucose analysis is carried out using a modified glucose oxidase-peroxidase methodology. The improvements in this technique include: i) a reduction in the delay of the analyzer to 90 s, making it suitable for application in a system for blood glucose regulation, ii) a minimal blood requirement of 3 ml/h, permitting long-term monitoring, iii) elimination of the need for systemic anticoagulation, iv) an excellent correlation (r = 0.993) between the measured whole blood glucose and the actual plasma glucose concentration, v) an average baseline drift of +0.5 mg%/h, vi) a sensitivity loss of less than 0.1%/h, and vii) a reasonable operating cost. This technique was implemented as part of a clinical apparatus known as an artificial endocrine pancreas which has been reliably applied in clinical and animal studies.

Adult↗
PubMed1987

Automated enzymatic measurement of lecithin, sphingomyelin, and phosphatidylglycerol in amniotic fluid.

We describe methods for automated enzymatic measurement of lecithin, sphingomyelin, and phosphatidylglycerol in amniotic fluid. Phospholipase C (EC 3.1.4.3) and sphingomyelin phosphodiesterase (EC 3.1.4.12) are reacted with lecithin and sphingomyelin, respectively, to liberate phosphocholine. Phosphocholine is then reacted with alkaline phosphatase, choline oxidase, peroxidase, and 4-aminoantipyrine to form a colored complex, for which the absorbance at 500 nm is measured with a centrifugal analyzer. Phosphatidylglycerol is hydrolyzed by phospholipase D (EC 3.1.4.4) to form glycerol, which is subsequently reacted with ATP and NAD+ in the presence of glycerol kinase and glycerol-3-phosphate dehydrogenase to yield NADH. The absorbance of the NADH formed is measured at 340 nm. These methods provide a simple, rapid, and accurate alternative to thin-layer chromatography for determination of phospholipids in amniotic fluid for assessment of fetal lung maturity.

Amniotic Fluid↗
PubMed1986

The cardiolipin antigen: chemistry and composition.

Cardiolipin, the primary lipid hapten in the antigen suspension used for the detection of antitreponemal antibodies in the sera of syphilitic patients, was successfully coupled to glucose oxidase, peroxidase, and some other enzymes using different crosslinking agents. These complexes were used to replace the pure uncomplexed cardiolipin for the preparation of the antigen suspension. When these suspensions were allowed to react with serum that contained anticardiolipin antibodies the activity of the enzyme was inhibited. In the absence of antibody, no enzyme inhibition was observed.

Antibodies, Bacterial↗
PubMed1984

[Use of cytochemical methods for diagnosis in fungicide research].

Cytochemical localization of acid and alkaline phosphatases, cytochrom c-oxidase, peroxidases and catalase was carried out on Phytophthora infestans (Mont.) de By. and Mucor mucedo (L.) Fres. First results are obtained about the influence of sublethal dosages of fungicidal compounds on the demonstration of these enzymes in the electron-microscope.

Acid Phosphatase↗
PubMed1982

Human red blood cell membrane oxidase and horseradish peroxidase cleavage of folic acid: evidence for formation of singlet oxygen.

1. Human red blood cell membrane oxidase catalyzes the transformation of folic acid to pterin-6-aldehyde and p-aminobenzoyl glutamic acid provided hydrogen peroxide, a xanthine oxidase inhibitor, is present. Horseradish peroxidase produces the same product in the absence of hydrogen peroxide. 2. The oxidation of folic acid by horseradish peroxidase is accompanied by photon emission. Several lines of evidence suggest that singlet oxygen is the emitting species and is generated directly: a) the effects of singlet oxygen traps such as bilirubin, and of singlet oxygen enhancers such as 1,4-diazobicyclo 2.2.2 octane (DABCO) and eosin; b) the emission spectrum maximum of the unsensitized reaction was greater than 560 nm; c) enhancement of photon emission when the reaction was carried out in D2O, and d) no enhancement of the emission was observed when anthracenic energy acceptors were present. 3. Singlet oxygen production and the inactivation of xanthine oxidase may be important when considering folic acid metabolism by cancer cells, in view of the fact that the level of this enzyme is low in these cells.

Animals↗
PubMed2004

Spongiform immobilization architecture of ionotropy polymer hydrogel coentrapping alcohol oxidase and horseradish peroxidase with octadecylsilica for optical biosensing alcohol in organic solvent.

An organic-phase optical alcohol biosensor consisting of alcohol oxidase and horseradish peroxidase coimmobilized in a spongiform hydrogel matrix of hydroxethyl carboxymethyl cellulose, an adduct of 3-methoxy-4-ethoxy benzaldehyde, 4-tert-butylpyridinium acetohydrazone, silica gel particles, and octadecylsilica particles in conjunction with an optical oxygen transducer has been successfully fabricated. The novel enzyme entrapment structure was mainly characterized with desirable solvent permeability, high efficiency of mass transfer for reactants, and good accessibility and stability of the immobilized enzymes. The biosensor could work in water-miscible solvent such as a solvent mixture of acetonitrile and phosphate aqueous buffer, as well as hydrophobic organic solvent such as n-hexane. The biosensor had the highest sensitivity to methanol in both solvent systems. Under the stop-flow mode, the biosensor had the analytical working ranges from 80 microM to 90 mM methanol in n-hexane and 0.10 to 90 mM methanol in acetonitrile/buffer. When the biosensor functioned in n-hexane, it could take benzaldehyde as an alcohol substrate and was free from any pH disturbance. In the presence of coimmobilized horseradish peroxidase, the operational life of the biosensor was 60 assays and the shelf life was longer than two weeks. The biosensor has been satisfactorily applied to the determination of methanol in commercial gasoline-methanol blend samples.

Alcohol Oxidoreductases↗
PubMed1984

A simple assay for monoamine oxidase using glutathione peroxidase and glutathione reductase.

A new fluorometric assay for the determination of monoamine oxidase activity that is applicable to any substrates including dopamine and serotonin is described. Hydrogen peroxide formed during the monoamine oxidase reaction was reduced in the presence of glutathione and glutathione peroxidase, and the oxidized glutathione was measured fluorometrically as NADP+ via oxidation of NADPH by glutathione reductase. This method was applied for inhibitor studies using clorgyline and deprenyl.

Animals↗
PubMed2000

Anoxia pretreatment protects soybean cells against H(2)O(2)-induced cell death: possible involvement of peroxidases and of alternative oxidase.

Anoxia followed by reoxygenation causes extensive damage to cellular components through generation of reactive oxygen intermediates. We examined cellular responses to oxidative stress after anoxia in cultured soybean or human fibroblast cells. Anoxia pretreatment protected soybean but not fibroblasts against H(2)O(2) concentrations that induced programmed cell death in normoxic cells. H(2)O(2) removal in anoxia-pretreated soybean cultures was faster. Protection was associated with increased action of alternative oxidase (AOX) and peroxidases. AOX inhibitors abolished the protective effect, while induction of AOX protected normoxic cells against H(2)O(2). We propose that during anoxia, plant cells can prepare for reoxygenation injury by up-regulating their antioxidant capacity, and that AOX is involved in this process.

Cell Death↗
PubMed1990

Targeted killing of yeast expressing a HIV-1 peptide by antibody-conjugated glucose oxidase and horseradish peroxidase.

The epitope recognized by monoclonal antibody directed against the HIV-1 recombinant gp160 protein was precisely delineated by using a number of peptides comprising amino acid positions 302-330 of the protein. Two different enzymes, glucose oxidase and horseradish peroxidase, were then coupled to distinct antibody molecules and the efficacy of the immunoenzymes in killing yeast cells which express the recognized peptide was evaluated by flow cytometry analysis. The antibody-glucose oxidase conjugate alone was cytotoxic only at large doses (over 35 micrograms/ml) while in the presence of the antibody-horseradish peroxidase conjugate, killing was observed at nine times lower concentrations (4 micrograms/ml). The procedure described here may provide a new immunotherapy tool for microbial infection.

Amino Acid Sequence↗
PubMed1990

Glutathione-S-transferase, superoxide dismutase, xanthine oxidase, catalase, glutathione peroxidase and lipid peroxidation in the liver of exercised rats.

Glutathione-S-transferase (GST), superoxide dismutase (SOD), Xanthine oxidase, selenium-dependent glutathione peroxidase (GPxI), catalase activities and malondialdehyde (MDA) content were determined in liver of three groups of exercised rats (E) viz., one day (E1), 10 days (E10) and 60 days (E60). GST, SOD and xanthine oxidase activities increased significantly with the increase in exercise period. Lipid peroxidation, expressed in terms of MDA formation, also increased in the liver of all the three groups. But catalase activity decreased significantly during exercise. Further, GPxI did not show any significant change in its activity in response to exercise. Our findings indicate that: 1) The significant increase in GST activity suggests their induction aimed at counteracting the oxidant stress induced during exercise; 2) The significant increase in xanthine oxidase and SOD activities indicates the generation of more superoxide anion radicals and their removal, respectively. 3) The significant reduction in catalase activity denotes the decreased formation of hydrogenperoxides during exercise; and 4) The pattern of changes in the activity level of GPxI indicate its least participation during exercise. However, in another way it is giving a scope for the involvement of GPxII associated with GST in the reduction of organic hydroperoxides. Further more, the relative increase in MDA is considered as the indicator of the rate of lipid peroxidation in the wake of exhaustive exercise.

Animals↗
PubMed1998

Oxygen metabolism in plant/bacteria interactions: effect of DPI on the pseudo-NAD(P)H oxidase activity of peroxidase.

Diphenyleneiodonium (DPI) has been used frequently as a specific inhibitor of NADH oxidase activity in studies of plant/pathogen interactions. The present study reports the effect of DPI on the pseudo-oxidative activity of horseradish peroxidase. DPI, like other phenolics, is able to catalytically stimulate NADH oxidation in the presence of exogenous H2O2. The stimulated NADH oxidation has an acidic pH optimum and has an apparent Km of 111 microM NADH. The NADH oxidation rate is linearly proportional to [DPI] and the amount of NADH oxidized is proportional to [H2O2]. Once exogenous H2O2 is depleted, the NADH oxidation is abruptly halted until additional H2O2 is supplied. In some respects DPI appears to mimic the effects of certain anti-oxidants that use HRP to scavenge H2O2 and NAD(P)H as a reductant.

Bacteria↗
PubMed1999

Catalytic and spectroscopic properties of cytochrome-c, horseradish peroxidase, and ascorbate oxidase embedded in a sol-gel silica matrix as a function of gelation time.

In this study, we investigated the optical features of the redox metal-dependent proteins cytochrome-c, horseradish peroxidase (HRP), and ascorbate oxidase embedded in a sol-gel-processed silica matrix as a function of gelation time. Circular dichroism, absorbance, and fluorescence spectroscopies revealed that the sol-gel process affects the complex structure of the dimeric ascorbate oxidase (although the prosthetic coppers still remain bound to the enzyme) but not that of monomeric cytochrome-c and HRP. Any modifications in ascorbate oxidase occurred in the initial gelation phase; the drying process induced no further alterations and the enzyme remained stable for months. Unfolding-refolding experiments on cytochrome-c revealed severely restricted motility in the protein moiety in the xerogel, the concentrated matrix that forms after drying. The diffusion time of the solvent within the matrix, which regulated the enzyme-substrate reaction rate, depended on the thickness of the monolith, not on the dryness of the specimen.

Ascorbate Oxidase↗
PubMed1994

Circular dichroism studies of the binding of mammalian and non-mammalian cytochromes c to cytochrome c oxidase, cytochrome c peroxidase, and polyanions.

The effects of binding of Candida krusei, Drosophila melanogaster, horse, human, and rat cytochromes c to beef cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase, EC 1.9.3.1) and yeast cytochrome c peroxidase (ferricytochrome c: hydrogen-peroxide oxidoreductase, EC 1.11.1.5) on their circular dichroism spectra were determined. The binding to cytochrome oxidase results in a positive increase in the ellipticities of the positive and negative Cotton effects at 404 nm and 417 nm of cytochrome c. The horse, human, and rat cytochromes c display less of an increase in the ellipticity of the positive Cotton effect at 404 nm, but more of a positive change in the negative Cotton effect at 417 nm than the C. krusei or D. melanogaster proteins. Interaction with yeast cytochrome c peroxidase elicits only a positive change in the ellipticity of the positive Cotton effect at 404 nm. No significant change is observed in the negative Cotton effect at 417 nm. Rat cytochrome c variants with a phenylalanine in place of tyrosine-67 and/or an alanine in place of proline-30 all display circular dichroism spectral changes upon binding to cytochrome c oxidase or cytochrome c peroxidase identical to those of the unaltered protein. The increase in ellipticity at 404 nm upon binding occurs even though replacement of tyrosine-67 results in the loss of the positive Cotton effect at this position. Polyglutamate and phosvitin complexes of cytochrome c show changes in the circular dichroism spectrum similar to those observed with cytochrome c peroxidase. However, the magnitudes of the spectral changes were considerably less. A model is proposed in which the main cause of the circular dichroism spectral changes observed upon complexation arise from the exclusion of solvent from the exposed front heme edge. According to this model, the exclusion of solvent changes the relative asymmetry of the environment of the electronic transitions of the heme prosthetic group of cytochrome c, resulting in observed circular dichroic effects.

Animals↗